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Prof. Dr. Thomas Lorenz


Phone : +49-221-470-3593

Fax:      +49-221-470-6708

Room:    223



  • thermodynamic and transport propoerties of correlated electron systems
  • low dimensional magnetism and quantum spin systems
  • (unconventional) superconductors
  • interplay of charge, spin, lattice and orbital degrees of freedom
  • transiton metal oxides
  • single crystal growth

Scientific career

Apl. Professor:

May 2015, University of Cologne


January 2010, University of Cologne

Anomalous Behavior of Spin Liquids: Thermodynamics and Heat Transport


October 1999 until September 2002: Scientific Assistant at the Institute of Physics II,  University of Cologne

October 1998 until September 1999: Post-Doc in the Oxide Spin Electronic Network (OXSEN) at the Laboratoire de l'Etat Solide and the Institut d'Electronique Fondamentale, Universite Paris-Sud, France. Research field: single crystal growth and studies of the magnetotransport properties of doped rare earth manganites and cobaltates.


July 1998, University of Cologne

Thesis: Thermodynamische Eigenschaften des Spin-Peierls-Systems CuGeO3 (ISBN 3-8265-4179-0)

Referees: Prof. Dr. R. Gross, Prof. Dr. A. Freimuth & Prof. Dr. A Klümper



July 1994, University of Cologne

Thesis: Aufbau eines Magnetkryostaten und Messungen der thermischen Ausdehnung von La1.87Sr0.13CuO4 im transversalen Magnetfeld

Referees: Prof. Dr. H. Micklitz, Prof. Dr. E. Müller-Hartmann

University studies:

1990-1994 University of Cologne, Germany

1989-1990 University of Vienna, Austria

1987-1989 University of Freiburg, Germany




Q. Faure, S. Takayoshi, S. Petit, V. Simonet, S. Raymond, L.-P. Regnault, M. Boehm, J.S. White, M. Mansson, Ch. Rüegg, P. Lejay, B. Canals, T. Lorenz, S.C. Furuya, T. Giamarchi, B. Grenier
Topological quantum phase transition in the Ising-like antiferromagnetic spin chain BaCo2V2O8
Nature Physics, 14, 716, 2018, arXiv:1706.05848

Zhe Wang, T. Lorenz, D.I. Gorbunov, P.T. Cong, Y. Kohama, S. Niesen, O. Breunig, J. Engelmayer, A. Herman, Jianda Wu, K. Kindo, J. Wosnitza, S. Zherlitsyn, A. Loidl
Quantum Criticality of an Ising-like Spin-1/2 Antiferromagnetic Chain in a Transverse Magnetic Field
Phys. Rev. Lett., 120, 207205, 2018, arXiv:1805.02392


Carl Rischau, Xiao Lin, Christoph Grams, Dennis Finck, Steffen Harms, Johannes Engelmayer, Thomas Lorenz, Yann Gallais, Benoit Fauqué, Joachim Hemberger, Kamran Behnia
A ferroelectric quantum phase transition inside the superconducting dome of Sr1-xCaxTiO3-δ
Nature Physics, 13, 643, 2017,

Oliver Breunig, Markus Garst, Andreas Klümper, Jens Rohrkamp, Mark M. Turnbull, Thomas Lorenz
Quantum criticality in the spin-1/2 Heisenberg chain system copper pyrazine dinitrate
Sci Adv, 3, eaao3773, 2017, arXiv:1709.00274

S. Kunkemöller, D. Brüning, A. Stunault, A.A. Nugroho, T. Lorenz, M. Braden
Magnetic shape-memory effect in SrRuO$_3$
Phys. Rev. B, 96, 220406(R), 2017, arXiv:1709.05688, PDF (5064 kB)


S. Holbein, M. Ackermann, L. Chapon, P. Steffens, A. Gukasov, A. Sazonov, O. Breunig, Y. Sanders, P. Becker, L. Bohaty, T. Lorenz, M. Braden
Strong magnetoelastic coupling at the transition from harmonic to anharmonic order in NaFe(WO4)2 with 3d5 configuration
Phys. Rev. B, 94, 104423, 2016, arXiv:1609.01849, PDF (4648 kB)


S. Scharffe, G. Kolland, M. Valldor, V. Cho, J.F. Welter, T. Lorenz
Heat transport of the spin-ice materials Ho2Ti2O7 and Dy2Ti2O7
J. Magn. Magn. Mater., 383, 83, 2015,, arXiv:1406.4037, PDF (620 kB)

O. Breunig, M. Garst, A. Rosch, E. Sela, B. Buldmann, P. Becker, L. Bohaty, R. Müller , T. Lorenz
Low-temperature ordered phases of the spin-1/2 XXZ chain system Cs2CoCl4
Phys. Rev. B, 91, 024423, 2015, arXiv:1412.2988, PDF (1315 kB)

S. Scharffe, O. Breunig, V. Cho, P. Laschitzky, M. Valldor, J. F. Welter, T. Lorenz
Suppression of Pauling's residual entropy in the dilute spin ice (Dy_(1-x)Y_x )2Ti2O7
Phys. Rev. B, 92, 180405(R), 2015, arXiv:1503.03856, PDF (576 kB)

P. Toledano, M. Ackermann, L. Bohaty, P. Becker, T. Lorenz, N. Leo, M. Fiebig
Primary ferrotoroidicity in antiferromagnets
Phys. Rev. B, 92, 094431, 2015, PDF (651 kB)

C. Ulrich, G. Khaliullin, M. Guennou, H. Roth, T. Lorenz, B. Keimer
Spin-orbital excitation continuum and anomalous electron-phonon interaction in the Mott insulator LaTiO$_3$
Phys. Rev. Lett., 115, 156403, 2015, arXiv:1509.05280, PDF (710 kB)

M. Ackermann , L. Andersen, T. Lorenz, L. Bohaty, P. Becker
Anisotropy study of multiferroicity in the pyroxene NaFeGe2O6
New J. Phys., 17, 013045, 2015, arXiv:1408.6772, PDF (8059 kB)


S. Scharffe, G. Kolland, M. Hiertz, M. Valldor, T. Lorenz
Hysteresis and Relaxation Effects in the Spin-Ice Compound Dy2Ti2O7 studied by Heat Transport
JPS Conf. Proc., 3, 014030, 2014, arXiv:1311.1139, PDF (632 kB)

S. K. Niesen, O. Breunig, S. Salm, M. Seher, M. Valldor, T. Lorenz
Substitution effects on the temperature vs. magnetic-field phase diagrams of the quasi-1D effective Ising spin-1/2 chain system BaCo2V2O8
Phys. Rev. B, 90, 104419, 2014, arXiv:1405.7273, PDF (1502 kB)

M. Ackermann, T. Lorenz, L. Bohaty, P. Becker
Magnetoelectric properties of A2[FeCl5(H2O)] with A = K, Rb, Cs
J. Phys.: Condens. Matter, 26, 506002, 2014, arXiv:1408.3997, PDF (1116 kB)


G. Kolland, M. Valldor, M. Hiertz, J. Frielingsdorf, T. Lorenz
Anisotropic Monopole Heat Transport in the Spin-Ice Compound Dy$_2$Ti$_2$O$_7$
Phys. Rev. B, 88, 054406, 2013, arXiv:1302.6114, PDF (450 kB)

S. K. Niesen, G. Kolland, M. Seher, O. Breunig, M. Valldor, M. Braden, B. Grenier, T. Lorenz
Magnetic phase diagrams, domain switching and a quantum phase transition of the quasi-1D Ising-like antiferromagnet BaCo2V2O8
Phys. Rev. B, 87, 224413, 2013, arXiv:1303.5599, PDF (3234 kB)

M. Ackermann, D. Brüning , T. Lorenz , P. Becker, L.Bohaty
Thermodynamic properties of the new multiferroic material (NH4)2[FeCl5(H2O)]
New J. Phys., 15, 123001, 2013, PDF (3997 kB)

O. Breunig, M. Garst, E. Sela, B. Buldmann, P. Becker, L. Bohaty, R. Müller, T. Lorenz
The spin-1/2 XXZ chain system Cs2 CoCl4 in a transverse magnetic field
Phys. Rev. Lett., 111, 187202, 2013, arXiv:1307.2870, PDF (334 kB)


A C. Komarek, M. Reuther, T. Lorenz, A. Cousson, P. Link, W. Morgenroth, D. Trots, C. Baehtz, M. Braden
Evidence for charge and orbital order in the doped titanates RE(1-x)CaxTiO3 (RE=Y, Er, Lu)
Submitted , Phys. Rev. Lett., 2012, arXiv:1109.0234

G. Kolland, O. Breunig, M. Valldor, M. Hiertz, J. Frielingsdorf, T. Lorenz
Thermal conductivity and specific heat of the spin-ice compound Dy2 Ti2 O7 : Experimental evidence for monopole heat transport
Phys. Rev. B, 86, 060402(R), 2012, arXiv:1205.5700, PDF (358 kB)

Z. Hu, Hua Wu, T.C. Koethe, S.N. Barilo, S.V. Shiryaev, G.L. Bychkov, C. Schüßler-Langeheine, T. Lorenz, A. Tanaka, H.H. Hsieh, H-J. Lin, C.T. Chen, N.B. Brookes, S. Agrestini, Y-Y. Chin, M. Rotter, L.H. Tjeng
Spin-state order/disorder and metal insulator transition in GdBaCo$_2$O$_{5.5}$: experimental determination of the underlying electronic structure
New J. Phys., 14, 123025, 2012


M. Valldor, O. Heyer, A. C. Komarek, A. Senyshyn, M. Braden, T. Lorenz
Magnetostrictive Neel ordering of the spin-5/2 ladder compound BaMn2O3: Distortion-induced lifting of geometrical frustration
Phys. Rev. B, 83, 024418, 2011, arXiv:1010.1183, PDF (897 kB)

S.K.Niesen, O. Heyer, T. Lorenz, M. Valldor
Antiferromagnetic Heisenberg S=5/2 spin chain compound SrMn2V2O8
J. Magn. Magn. Mater., 323, 2575, 2011, arXiv:1103.1830

M. K. Forthaus, G. R. Hearne, N. Manyala, O. Heyer, R. A. Brand, D. I. Khomskii, T. Lorenz, M. M. Abd-Elmeguid
Pressure-induced quantum phase transition in Fe1−xCoxSi (x = 0.1,0.2)
Phys. Rev. B, 83, 085101, 2011, PDF (1294 kB)

O. Heyer, T. Lorenz, V. B. Zabolotnyy, D. V. Evtushinsky, S. V. Borisenko, I. Morozov, L. Harnagea, S. Wurmehl, C. Hess, B. Büchner
Resistivity and Hall effect of LiFeAs: Evidence for electron-electron scattering
Phys. Rev. B, 84, 064512, 2011, arXiv:1010.2876, PDF (355 kB)

O. Heyer, P. Link, D. Wandner, U Ruschewitz, T. Lorenz
Thermodynamic properties and resistivity of the ferromagnetic semiconductor EuC2
New J. Phys., 13, 113041, 2011, arXiv:1103.0980, PDF (752 kB)

N. Hollmann, M. W. Haverkort, M. Benomar, M. Cwik, M. Braden, T. Lorenz
Evidence for a temperature-induced spin-state transition of Co3+ in La2-xSrxCoO4
Phys. Rev. B, 83, 174435, 2011, arXiv:1204.0730, PDF (377 kB)

G. Giovannetti, A. Stroppa, S. Picozzi, D. Baldomir, V. Pardo, S. Blanco-Canosa, F. Rivadulla, S. Jodlauk, D. Niermann, J. Rohrkamp, T. Lorenz , S. Streltsov, D.I. Khomskii, J. Hemberger
Dielectric properties and magnetostriction of the collinear multiferroic spinel CdV2O4
Phys. Rev. B, 83, 060402(R), 2011

A. C. Komarek, M. Isobe, J. Hemberger, D. Meier, T. Lorenz, D. Trots, A. Cervellino, M. T. Fernández-Díaz, Y. Ueda, M. Braden
Dimerization and Charge Order in Hollandite K2V8O16
Phys. Rev. Lett., 107, 027201, 2011

A.V. Kalinov, O.Yu. Gorbenko, A.N. Taldenkov, J. Rohrkamp, O. Heyer, S. Jodlauk, N.A. Babushkina, L.M. Fisher, A.R. Kaul, D.I. Khomskii, K.I. Kugel, T. Lorenz
Phase Diagram of Spin States and Magnetic Interactions in Isotope Substituted (Pr,Eu)0.7Ca0.3CoO3
Solid State Phenomena, 168-169, 465, 2011, PDF (215 kB)


H. Banks, N. J. Hillier, J. S. Schilling, J. Rohrkamp, T. Lorenz, J. A. Mydosh, T. Fickenscher, R. Pöttgen
Dependence of the magnetic ordering temperature on hydrostatic pressure for the ternary intermetallic compounds GdAgMg, GdAuMg, EuAgMg, and EuAuMg
Phys. Rev. B, 81, 212403, 2010, PDF (388 kB)

A. V. Kalinov, O. Yu. Gorbenko, A. N. Taldenkov, J. Rohrkamp, O. Heyer, S. Jodlauk, N. A. Babushkina, L. M. Fisher, A. R. Kaul, A. A. Kamenev, T. G. Kuzmova, D. I. Khomskii, K. I. Kugel, T. Lorenz
Phase diagram and isotope effect in (Pr1−yEuy)0.7Ca0.3CoO3 cobaltites exhibiting spin-state transitions
Phys. Rev. B, 81, 134427, 2010, arXiv:0909.2978, PDF (891 kB)

J. Rohrkamp, M.D. Phillips, M.M. Turnbull, T. Lorenz
Thermal expansion of the spin-1/2 Heisenberg-chain compound Cu(C4H4N2)(NO3)2
JPCS, 200, 012169, 2010, arXiv:0907.0400, PDF (4985 kB)

Sina Zimmermann, Matthias Brühmann, Frederick Casper, Oliver Heyer, Thomas Lorenz, Claudia Felser, Anja-Verena Mudring, Gerd Meyer
Eight-Coordinate Endohedral Rhenium, Osmium and Iridium Atoms in Rare- Earth Halide Cluster Complexes
Eur. J. Inorg. Chem., 18, 2613, 2010, PDF (832 kB)

D. Wandner, P. Link, O. Heyer, J. Mydosh, M. A. Ahmida, M. M. Abd-Elmeguid, M. Speldrich, H. Lueken, U. Ruschewitz
Structural Phase Transitions in EuC2
Inorg. Chem., 49, 312, 2010

N. A. Babushkina, A. N. Taldenkov, A. V. Kalinov, L. M. Fisher, O. Yu. Gorbenko, T. Lorenz, D. I. Khomskii, K. I. Kugel
Isotope Effect and Characteristic Features of the Phase Diagram for Cobaltites with Spin State Transitions
JETP, 111, 189, 2010, PDF (220 kB)

M. K. Forthaus, K. Sengupta, O. Heyer, N. E. Christensen, A. Svane, K. Syassen, D. I. Khomskii, T. Lorenz, M. M. Abd-Elmeguid
Superconductivity in SnO: A Nonmagnetic Analog to Fe-Based Superconductors?
Phys. Rev. Lett., 105, 157001, 2010, arXiv:1009.3787

A. Senyshyn, B. Schwarz, T. Lorenz, V. T. Adamiv, Ya. V. Burak, J. Banys, R. Grigalaitis, L. Vasylechko, H. Ehrenberg, H. Fuess
Low-temperature crystal structure, specific heat, and dielectric properties of lithium tetraborate Li2B4O7
J. Appl. Phys., 108, 093524, 2010, PDF (490 kB)


M. Cwik, M. Benomar, T. Finger, Y. Sidis, D. Senff, M. Reuther, T. Lorenz , M. Braden
Magnetic Correlations in La2-xSrxCoO4 Studied by Neutron Scattering: Possible Evidence for Stripe Phases
Phys. Rev. Lett., 102, 057201, 2009, arXiv:0808.0106, PDF (585 kB)

A. V. Sologubenko, T. Lorenz, J. A. Mydosh, B. Thielemann, H. M. Rønnow, Ch. Rüegg, K. W. Krämer
Evidence for spinon localization in the heat transport of the spin-1 2 ladder compound (C5H12N)2CuBr4
Phys. Rev. B, 80, 220411(R), 2009, arXiv:0909.5180, PDF (245 kB)

C. Ulrich, L. J. P. Ament, G. Ghiringhelli, L. Braicovich, M. Moretti Sala, N. Pezzotta, T. Schmitt, G. Khaliullin, J. van den Brink, H. Roth, T. Lorenz, B. Keimer
Momentum Dependence of Orbital Excitations in Mott-Insulating Titanates
Phys. Rev. Lett., 103, 107205, 2009, arXiv:0908.2497, PDF (298 kB)

M. Kriener, M. Braden, H. Kierspel, D. Senff, O. Zabara, C. Zobel, T. Lorenz
Magnetic and structural transitions in La1−xAxCoO3 (A=Ca, Sr, and Ba)
Phys. Rev. B, 79, 224104, 2009, arXiv:0801.4188, PDF (1820 kB)


A. Gössling, R. Schmitz, H. Roth, M.W. Haverkort, T. Lorenz, J.A. Mydosh, E. Müller-Hartmann, M. Grüninger
Mott-Hubbard exciton in the optical conductivity of YTiO3 and SmTiO3
Phys. Rev. B, 78, 075122, 2008, arXiv:cond-mat/0608531, PDF (378 kB)

K. Berggold, M. Kriener, P. Becker, M. Benomar, M. Reuther, C. Zobel, T. Lorenz
Anomalous expansion and phonon damping due to the Co spin-state transition in RCoO3 (R=La, Pr, Nd, and Eu)
Phys. Rev. B, 78, 134402, 2008, arXiv:0803.1957, PDF (687 kB)

N. Johannsen, S. Süllow, A.V. Sologubenko, T. Lorenz, J.A. Mydosh
Magneto-thermal evidence of a partial gap at the Fermi surface of UPt2Si2
Phys. Rev. B, 78, 121103(R), 2008, arXiv:0804.1318, PDF (275 kB)

D. Senff, O. Schumann, M. Benomar, M. Kriener, T. Lorenz, Y. Sidis, K. Habicht, P. Link, M. Braden
Melting of magnetic correlations in charge-orbital ordered La1/2Sr3/2MnO4: competition of ferro and antiferromagnetic states
Phys. Rev. B, 77, 184413, 2008, arXiv:0801.1787, PDF (757 kB)

T. Lorenz, O. Heyer, M. Garst, F. Anfuso, A. Rosch, Ch. Rüegg, K. Krämer
Diverging thermal expansion of the spin-ladder system (C5H12N)2CuBr4
Phys. Rev. Lett., 100, 067208, 2008, arXiv:0711.1510, PDF (712 kB)

A.V. Sologubenko, T. Lorenz, J.A. Mydosh, A. Rosch, K.C. Shortsleeves, M.M. Turnbull
Field-dependent thermal transport in the Haldane chain compound NENP
Phys. Rev. Lett., 100, 137202, 2008, arXiv:0712.3991, PDF (304 kB)

A.V. Sologubenko, K. Berggold, T. Lorenz, A. Rosch, E. Shimshoni, M.D. Phillips, M.M. Turnbull
Magnetic field-dependent thermal transport in a spin-1/2 chain compound
Physica B, 403, 1445, 2008

D. Bichler, V. Zinth, D. Johrendt, O. Heyer, M.K. Forthaus, T. Lorenz, M.M. Abd-Elmeguid
Structural and magnetic phase transitions of the V4-cluster compound GeV4S8
Phys. Rev. B, 77, 212102, 2008, PDF (282 kB)

C. Ulrich, G. Ghiringhelli, A. Piazzalunga, L. Braicovich, N.B. Brookes, H. Roth, T. Lorenz, B. Keimer
Orbital excitations in YTiO3 and LaTiO3 probed by resonant inelastic soft x-ray scattering
Phys. Rev. B, 77, 113102, 2008, PDF (242 kB)

F. Anfuso, M. Garst, A. Rosch, O. Heyer, T. Lorenz, Ch. Rüegg, K. Krämer
Spin-spin correlations of the spin-ladder compound (C5H12N)2CuBr4 measured by magnetostriction and comparison to Quantum Monte Carlo results
Phys. Rev. B, 77, 212102, 2008, arXiv:0803.1072, PDF (829 kB)


I. Loa, X. Wang, K. Syassen, H. Roth, T. Lorenz, M. Hanfland, Y.-L. Mathis
Crystal structure and the Mott–Hubbard gap in YTiO3 at high pressure
J. Phys.: Condens. Matter, 19, 406223, 2007,, PDF (610 kB)

A. C. Komarek, H. Roth, M. Cwik, W.-D. Stein, J. Baier, M. Kriener, F. Bourée, T. Lorenz, M. Braden
Magnetoelastic coupling in RETiO3 (RE = La, Nd, Sm, Gd, Y) investigated with diffraction techniques and thermal expansion measurements
Phys. Rev. B, 75, 224402, 2007,, PDF (863 kB)

J. Rohrkamp, O. Heyer, T. Fickenscher, R. Pöttgen, S. Jodlauk, H. Hartmann, T. Lorenz, J.A. Mydosh
Thermal expansion of the magnetically ordering intermetallics RTMg (R = Eu, Gd and T = Ag, Au)
J. Phys.: Condens. Matter, 19, 486204, 2007, arXiv:0708.2817v1, PDF (493 kB)

A.V. Sologubenko, K. Berggold, T. Lorenz, A. Rosch, E. Shimshoni, M.D. Phillips, M.M. Turnbull
Magnetothermal transport in the spin-1/2 chains of copper pyrazine dinitrate
Phys. Rev. Lett., 98, 107201, 2007, arXiv:cond-mat/0612486, PDF (279 kB)

T. Lorenz, S. Stark, O. Heyer, N. Hollmann, A. Vasiliev, A. Oosawa, H. Tanaka
Thermodynamics of the coupled spin-dimer system TlCuCl3 close to a quantum phase transition
J. Magn. Magn. Mater., 316, 291, 2007, arXiv:cond-mat/0609348), PDF (531 kB)

R. Lengsdorf, J.-P. Rueff, G. Vanko, T. Lorenz, L. H. Tjeng, M. M. Abd-Elmeguid
Spin-state-driven metal-insulator transition in (La,Sr)CoO3 under high-pressure
Phys. Rev. B, 75, 180401(R), 2007, PDF (176 kB)

K. Berggold, J. Baier, D. Meier, J.A. Mydosh, T. Lorenz, J. Hemberger, A. Balbashov, N. Aliouane, D.N. Argyriou
Anomalous thermal expansion and strong damping of the thermal conductivity of NdMnO3 and TbMnO3 due to 4f crystal-field excitations
Phys. Rev. B, 76, 094418, 2007, arXiv:cond-mat/0703222, PDF (529 kB)

D. Meier, N. Aliouane, D.N. Argyriou, J.A. Mydosh, T. Lorenz
New features in the phase diagram of TbMnO3
New J. Phys., 9, 100, 2007,, PDF (976 kB)

J. Baier, P. Steffens, O. Schumann, M. Kriener, S. Stark, H. Hartmann, O. Friedt, A. Revcolevschi, P.G. Radaelli, S. Nakatsuji, Y. Maeno, J.A. Mydosh, T. Lorenz, M. Braden
Magnetoelastic coupling across the metamagnetic transition in Ca2-xSrxRuO4 (0.2 ≤ x ≤ 0.5)
J. Low Temp. Phys., 147, 405, 2007, arXiv:cond-mat/0610769

S. Jodlauk, P. Becker, J. A. Mydosh, D. I. Khomskii, T. Lorenz, S. V. Streltsov, D. C. Hezel, L. Bohaty
Pyroxenes: A new class of multiferroics
J. Phys.: Condens. Matter, 19, 432201, 2007, arXiv:0709.1125, PDF (975 kB)

N. Johannsen, Th. Wolf, A.V. Sologubenko, T. Lorenz, A. Freimuth, J.A. Mydosh
Nernst Effect in NdBa2[Cu1-yNiy]3O7-δ
Phys. Rev. B, 76, 020512(R), 2007, arXiv:0706.1463, PDF (417 kB)

M. Kriener, M. Braden, D. Senff, O. Zabara, T. Lorenz
Evidence for Multiple Phase Transitions in La1-xCaxCoO3
J. Magn. Magn. Mater., 310, e187, 2007, arXiv:cond-mat/0605721

S. Stark, O. Heyer, A. Vasiliev, A. Oosawa, H. Tanaka, T. Lorenz
Thermodynamic properties of the field-induced Neel order of TlCuCl3
J. Magn. Magn. Mater., 310, 1374, 2007, arXiv:cond-mat/0610487

J. Baier, D. Meier, K. Berggold, J. Hemberger, A. Balbashov, J.A. Mydosh, T. Lorenz
Uniaxial pressure dependencies of the phase transitions in GdMnO3
J. Magn. Magn. Mater., 310, 1165, 2007, arXiv:cond-mat/0605515

K. Kordonis, A.V. Sologubenko, T. Lorenz, S.-W. Cheong, A. Freimuth
Spin thermal conductivity of the Haldane chain compound Y2BaNiO5
J. Magn. Magn. Mater., 310, 1245, 2007

A.V. Sologubenko, T. Lorenz, H.R. Ott, A. Freimuth
Thermal conductivity via magnetic excitations in spin-chain materials
J. Low Temp. Phys., 147, 387, 2007, arXiv:cond-mat/0611052


Maurits W. Haverkort, Zhiwei Hu, Júlio C. Cezar, Tobias Burnus, Helena Hartmann, Marco Reuther, Christian Zobel, Thomas Lorenz, Arata Tanaka, Nicholas B. Brookes, Hui-Huang Hsieh, Hong-Ji Lin, Chien-Te Chen, L. Hao Tjeng
Spin State Transition in LaCoO3 Studied Using Soft X-ray Absorption Spectroscopy and Magnetic Circular Dichroism
Phys. Rev. Lett., 97, 176405, 2006,, PDF (560 kB)

C. Ulrich, A. Gössling, M. Grüninger, M. Guennou, H. Roth, M. Cwik, T. Lorenz, G. Khaliullin, B. Keimer
Raman Scattering in the Mott Insulators LaTiO3 and YTiO3: Evidence for Orbital Excitations
Phys. Rev. Lett., 97, 157401, 2006,, PDF (1261 kB)

Jan Gegner, Thomas C. Koethe, Hua Wu, Zhiwei Hu, Helena Hartmann, T. Lorenz, T. Fickenscher, R. Pöttgen, L. Hao Tjeng
Electronic structure of RAuMg and RAgMg (R = Eu, Gd, Yb)
Phys. Rev. B, 74, 073102, 2006,, PDF (516 kB)

J. Baier, T. Zabel, M. Kriener, P. Steffens, O. Schumann, O. Friedt, A. Freimuth, A. Revcolevschi, S. Nakatsuji, Y. Maeno, T. Lorenz, M. Braden
Thermodynamic Properties of (Ca,Sr)2RuO4 in Magnetic Fields
Physica B, 378, 497, 2006,

K. Berggold, T. Lorenz, J. Baier, M. Kriener, D. Senff, S. Barilo, A. Freimuth
Thermal conductivity of R2CuO4, with R = La, Pr and Gd
Physica B, 378, 1064, 2006,

K. Berggold, T. Lorenz, J. Baier, M. Kriener, D. Senff, H. Roth, A. Severing, H. Hartmann, A. Freimuth, S. Barilo, F. Nakamura
Magnetic heat transport in R2CuO4 (R = La, Pr, Nd, Sm, Eu, and Gd)
Phys. Rev. B, 73, 10, 104430, 2006,

O. Heyer, N. Hollmann, I. Klassen, S. Jodlauk, L. Bohatý, P. Becker, J.A. Mydosh, T. Lorenz, D.I. Khomskii
A new multiferroic material: MnWO4
J. Phys.: Condens. Matter, 18, L471-L475, 2006

N. Johannsen, A. Oosawa, H. Tanaka, A. Vasiliev, T. Lorenz
Uniaxial pressure dependencies of the phase boundary of TlCuCl
Physica B, 378-380, 1043, 2006, arXiv:condmat/0507582

K. Kordonis, A.V. Sologubenko, T. Lorenz, S.-W. Cheong, A. Freimuth
Spin thermal conductivity of the Haldane chain compound Y2BaNiO5
Phys. Rev. Lett., 97, 11, 115901, 2006, arXiv:cond-mat/0603586, PDF (270 kB)

K. Berggold, M. Kriener, C. Zobel, A. Reichl, M. Reuther, R. Müller, A. Freimuth, T. Lorenz
Thermal Conductivity, Thermopower, and Figure of Merit of La1-xSrxCoO3
Phys. Rev. B, 72, 155116, 2006, arXiv:cond-mat/0501262

J. Baier, D. Meier, K. Berggold, J. Hemberger, A. Balbashov, J.A. Mydosh, T. Lorenz
Hysteresis effects in the phase diagram of multiferroic GdMnO3
Phys. Rev. B, 73, 10, 100402(R), 2006, arXiv:cond-mat/0601169, PDF (547 kB)


M. Kriener, P. Steffens, J. Baier, O. Schumann, T. Zabel, T. Lorenz, O. Friedt, R. Mueller, A. Gukasov, P. Radaelli, P. Reutler, A. Revcolevschi, S. Nakatsuji, Y. Maeno, M. Braden
Structural aspects of metamagnetism in Ca2-xSrxRuO4 (0.2 < x < 0.5): field tuning of orbital occupation
Phys. Rev. Lett., 95, 26, 267403, 2005,,

R. Rückamp, J. Baier, M. Kriener, M.W. Haverkort, T. Lorenz, G.S. Uhrig, L. Jongen, A. Möller, G. Meyer, M. Grüninger
Zero-field incommensurate spin-Peierls phase with interchain frustration in TiOCl
Phys. Rev. Lett., 95, 097203, 2005,, PDF (365 kB)

R. Rückamp, E. Benckiser, M.W. Haverkort, H. Roth, T. Lorenz, A. Freimuth, L. Jongen, A. Möller, G. Meyer, P. Reutler, B. Büchner, A. Revcolevschi, S.-W. Cheong, C. Sekar, G. Krabbes, M. Grüninger
Optical study of orbital excitations in transition-metal oxides
New J. Phys., 7, 1, 144, 2005,, PDF (1463 kB)

M. W. Haverkort, Z. Hu, A. Tanaka, G. Ghiringehelli, H. Roth, M. Cwik, T. Lorenz, C. Schüßler-Langeheine, S. V. Streltsov, A. S. Mylnikova, V. I. Anisimov, C. de Nadai, N. B. Brookes, H. H. Hsieh, H.-J. Lin, C. T. Chen, T. Mizokawa, Y. Taguchi, Y. Tokura, D. I. Khomskii, L. H. Tjeng
Determination of the Orbital Moment and Crystal-Field Splitting in LaTiO3
Phys. Rev. Lett., 94, 056401, 2005,, PDF (270 kB)

O. Volkova, Yu. Arango, N. Tristan, V. Kataev, E. Gudilin, D. Meier, T. Lorenz, B. Büchner, A. Vasil'ev
Nature of Low-Temperature Phase Transitions in CaMn7O12
JETP Letters, 82, 444, 2005

N. Johannsen, A. Vasiliev, A. Oosawa, H. Tanaka, T. Lorenz
Magnetoelastic Coupling in the Spin-Dimer System TlCuCl3
Phys. Rev. Lett., 95, 017205, 2005, arXiv:cond-mat/0412451

J. Baier, S. Jodlauk, M. Kriener, A. Reichl, C. Zobel, H. Kierspel, A. Freimuth, T. Lorenz
Spin-State Transition and Metal-Insulator Transition in La1-xEuxCoO3
Phys. Rev. B, 71, 014443, 2005, arXiv:cond-mat/0405680

H. Hartmann, K. Berggold, S. Jodlauk, I. Klassen, K. Kordonis, T. Fickenscher, R. Pöttgen, A. Freimuth, T. Lorenz
Magnetoresistance, specific heat and magnetocaloric effect of equiatomic rare-earth transition-metal magnesium compounds
J. Phys.: Condens. Matter, 17, 7731, 2005, arXiv:cond-mat/0508528

M. Braden, O. Friedt, O. Schumann, J. Baier, P. Steffens, M. Kriener, T. Lorenz, F. Bouree, G. Andre, A. Gukasov, P.G. Radaelli, S. Nakastuji, und Y. Maeno
The phase-diagram of Ca2¡xSrxRuO4 : relation between crystal distortions and and physical properties
Mat. Res. Soc. Symp. Proc., 840, 71, 2005


Z. Hu, Hua Wu, M. W. Haverkort, H. H. Hsieh, H. -J. Lin, T. Lorenz, J. Baier, A. Reichl, I. Bonn, C. Felser, A. Tanaka, C. T. Chen, L. H. Tjeng
Different Look at the Spin State of Co3+ Ions in a CoO5 Pyramidal Coordination
Phys. Rev. Lett., 92, 20, 207402, 2004,, PDF (283 kB)

M. Kriener, C. Zobel, A. Reichl, J. Baier, M. Cwik, K. Berggold, H. Kierspel, O. Zabara, A. Freimuth, T. Lorenz
Structure, Magnetization and Resistivity of La1-xMxCoO3 (M = Ca, Sr, and Ba)
Phys. Rev. B, 69, 094417, 2004, arXiv:cond-mat/0401400, PDF (132 kB)

R. Lengsdorf, M. Ait-Tahar, S.S. Saxena, M. Ellerby, D.I. Khomskii, H. Micklitz, T. Lorenz, M.M. Abd-Elmeguid
Pressure-induced insulating state in (La,Sr)CoO3
Phys. Rev. B, 69, 140403(R), 2004, arXiv:cond-mat/0504282, PDF (64 kB)


M. Cwik, T. Lorenz, J. Baier, R. Mueller, G. Andre, F. Bouree, F. Lichtenberg, A. Freimuth, E. Mueller-Hartmann, M. Braden
Crystal and magnetic structure of LaTiO3 : evidence for non-degenerate t2g-orbitals
Phys. Rev. B, 68, 6, 060401, 2003,,, PDF (159 kB)

M. Hofmann, T. Lorenz, K. Berggold, M. Grüninger, A. Freimuth, G.S. Uhrig, E. Brück
Evidence for a large magnetic heat current in insulating layered cuprates
Phys. Rev. B, 67, 18, 184502, 2003, arXiv:cond-mat/0301093, PDF (64 kB)

G. Maris, Y. Ren, V. Volotchaev, C. Zobel, T. Lorenz, T. T. M. Palstra
Evidence for orbital ordering in LaCoO3
Phys. Rev. B, 67, 22, 224423, 2003, PDF (52 kB)

M. Markina, A. Vasiliev, J. Müller, M. Lang, K. Kordonis, T. Lorenz, M. Isobe, Y. Ueda
Thermal properties of NaV2O5
J. Magn. Magn. Mater., 258, 398, 2003


C. Zobel, M. Kriener, D. Bruns, J. Baier, M. Grüninger, T. Lorenz, P. Reutler, A. Revcolevschi
Evidence for a low-spin to intermediate-spin state transition in LaCoO3
Phys. Rev. B, 66, 020402(R), 2002, arXiv:cond-mat/0205479, PDF (81 kB)

M. Hofmann, T. Lorenz, A. Freimuth, G.S. Uhrig, H. Kageyama, Y. Ueda, G. Dhalenne, A. Revcolevschi
Heat Transport in SrCu2(BO3)2 and CuGeO3
Physica B, 312-313, 597, 2002, arXiv:cond-mat/0108488

T. Lorenz, M. Hofmann, M. Grüninger, A. Freimuth, G.S. Uhrig, M. Dumm, M. Dressel
Evidence for spin-charge separation in quasi-one-dimensional organic conductors (This article has been retracted!)
Nature (London), 418, 614, 2002, PDF (51 kB)

M. Grüninger, R. Rückamp, M. Windt, P. Reutler, C. Zobel, T. Lorenz, A. Freimuth, A. Revcolevschi
Experimental Quest for Orbital Waves
Nature (London), 418, 39, 2002


M. Hofmann, T. Lorenz, G.S. Uhrig, H. Kierspel, O. Zabara, A. Freimuth, H. Kageyama, Y. Ueda
Strong Damping of Phononic Heat Current by Magnetic Exitations in SrCu2(BO3)2
Phys. Rev. Lett., 87, 047202, 2001, arXiv:cond-mat/0103012, PDF (243 kB)


B. Büchner, T. Lorenz, R. Walter, H. Kierspel, A. Revcolevschi, G. Dhalenne
Spin-Peierls order parameter and antiferromagnetism in the dimerized and incommensurate phases of Zn-doped CuGeO3
Phys. Rev. B, 59, 6886, 1999

D. Bruns, B. Büchner, R. Gross, T. Lorenz, S. Uchida
Thermal expansion of La1.85Sr0.15CuO4 in magnetic fields up to 14 Tesla
J. Low Temp. Phys., 117, 1453, 1999


T. Lorenz, B. Büchner, P.H.M. van Loosdrecht, F. Schönfeld, G. Chouteau, A. Revcolevschi, G. Dhalenne
Incommensurate phase of CuGeO3: from solitons to sinusoidal modulation
Phys. Rev. Lett., 81, 148, 1998, PDF (222 kB)

M. Fischer, P.H.M. van Loosdrecht, G. Güntherodt, B. Büchner, T. Lorenz, M. Breuer, J. Zeman, G. Martinez, G. Dhalenne, A. Revcolevschi
Revival of the spin--Peierls transition in Cu1-xZnxGeO3 under pressure
Phys. Rev. B, 57, 7749, 1998, PDF (128 kB)

K. Fabricius, A. Klümper, U. Löw, B. Büchner, T. Lorenz, G. Dhalenne, A. Revcolevschi
Reexamination of the microscopic couplings of the quasi-one-dimensional antiferromagnet CuGeO3
Phys. Rev. B, 57, 1102, 1998, PDF (125 kB)

S. Uma, W. Schnelle, E. Gmelin, G. Rangarajan, S. Skanthakumar, J.W. Lynn, R. Walter, T. Lorenz, B. Büchner, A. Erb
Magnetic Ordering in Single Crystals of PrBa2Cu3O7-d
J. Phys.: Condens. Matter, 10, L33, 1998, PDF (125 kB)


T. Lorenz, U. Ammerahl, T. Auweiler, B. Büchner, A. Revcolevschi, G. Dhalenne
Temperature and magnetic-field dependence of the lattice constant in the spin-Peierls cuprate CuGe03 studied by capacitance dilatometry in fields up to 16 T
Phys. Rev. B, 55, 5914, 1997, PDF (315 kB)

U. Ammerahl, T. Lorenz, B. Büchner, A. Revcolevschi, G. Dhalenne
Magnetostriction of the spin-Peierls cuprate CuGe03
Z. Phys. B, 102, 71, 1997

U. Köbler, J. Schweizer, P. Chieux, T. Lorenz, B. Büchner, W. Schnelle, F. Deloie, W. Zinn
Evidence for biquadratic exchange interactions in GdAg1-xZnx
J. Magn. Magn. Mater., 170, 110, 1997, PDF (11451 kB)

U. Ammerahl, T. Lorenz, B. Büchner, A. Revcolevschi, G. Dhalenne
Magnetostriction of the spin-Peierls cuprate CuGe03
Z. Phys. B, 102, 71, 1997, PDF (574 kB)

T. Lorenz, H. Kierspel, S. Kleefisch, B. Büchner, E. Gamper, A. Revcolevschi, G. Dhalenne
Specific heat, thermal expansion, and pressure dependencies of the transition temperatures of doped CuGe03
Phys. Rev. B, 56, R501, 1997, PDF (114 kB)


T. Lorenz, U. Ammerahl, R. Ziemes, B. Büchner, A. Revcolevschi, G. Dhalenne
Thermodynamic properties of the incommensurate phase of CuGe03
Phys. Rev. B, 54, R15610, 1996, PDF (96 kB)

B. Büchner, U. Ammerahl, T. Lorenz, W. Brenig, G. Dhalenne, and A. Revcolevschi
Magnetic Frustration Induced Formation of the Spin-Peierls Phase in CuGe03: Experimental Evidence
Phys. Rev. Lett., 77, 1624, 1996, PDF (144 kB)


Th. Auweiler, T. Lorenz, W. Schlabitz, H. Kierspel, B. Büchner, A. Freimuth, H. Micklitz, I. Tanaka, H. Kojima
Thermal Expansion of a La1.87Sr0.13CuO4 Single Crystal at Tc in High Magnetic Fields
Physica C, 235, 1931, 1994, PDF (248 kB)



M.W. Haverkort, Z. Hu, J.C. Cezar, T. Burnus, H. Hartmann, M. Reuther, C. Zobel, T. Lorenz, A. Tanaka, N.B. Brookes, H.H. Hsieh, H.-J. Lin, C.T. Chen, L.H. Tjeng
Spin state transition in LaCoO3 studied using soft X-ray absorption spectroscopy and magneic circular dichrosim
, 2007, PDF (312 kB)

PhD thesis


T. Lorenz
Thermodynamische Eigenschaften des Spin-Peierls-Systems CuGeO3
, PhD thesis, Universität zu Köln, 1998, PDF (2232 kB)

Diploma thesis


T. Lorenz
Aufbau eines Magnetkryostaten und Messungen der thermischen Ausdehnung von La1.87Sr0.13CuO4 im transversalen Magnetfeld
, Diploma thesis, Universität zu Köln, 1994

In Proceedings


T. Lorenz
Magnetic frustration and spin-Peierls transition in CuGeO3
, B. Kramer, Advances in Solid State Physics, 39, Vieweg Verlag, Braunschweig, 1999, PDF (1123 kB)