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The European Physical Journal B
ISSN: 1434-6028 (printed version)
ISSN: 1434-6036 (electronic version)
Abstract Volume 3 Issue 2 (1998) pp 185-188
Magnetic phase diagram of perovskite Mn oxides at $\mathsf{T=0}$
Y. Liu (1), J. Dong (2) (a), D.Y. Xing (3)
(1) Department of Physics, Nanjing University, Nanjing 210008, P.R. China
(2) National Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210008, P.R. China
(3) Center for Advanced Studies in Science and Technology of Microstructures, Nanjing 210093, P.R. China
Received: 11 July 1996 / Revised: 7 December 1996 / Accepted: 24 July 1997
Abstract: Minimizing total free energy by numerical calculations, we obtain the magnetic phase diagram of perovskite Mn oxides, such as $({\rm La}_{1-x} {\rm X}_x){\rm MnO}_3$with $\rm X=Ba$, Ca, Sr, etc. in the whole doping region from x=0 to x=1 at temperature T=0. It is discovered that a spiral state is stable in a low concentration of X ions while a canted state is stable in a high concentration of X ions, and a ferromagnetic phase can exist in the intermediate concentrations when the antiferromagnetic interaction is weak. The energy difference between spiral and canted states is found to be small when the Hund coupling is large. Magnetic field induced spiral/canted phase transition is considered as a possible mechanism of the colossal magnetoresistance (CMR) in the Mn oxides.
PACS. 71.27.+a Strongly correlated electron systems; heavy fermions - 72.15.Gd Galvanomagnetic and other magnetotransport effects - 75.10.-b General theory and models of magnetic ordering
(a) email: zyq@netra.nju.edu.cn
Article in PDF-Format (276 KB)
Online publication: July 9, 1998
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