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Magnetic properties of low-doped Nd1-xCaxMnO3 manganites

Vladimir A. Khomchenko 1Igor Troyanchuk 1Henryk Szymczak Ritta Szymczak 2

1. The Institute of Solid State & Semiconductor Physics, National Academy of Science of Belarus, 17 P.Brovka, Minsk 220072, Belarus
2. Polish Academy of Sciences, Institute of Physics, al. Lotników 32/46, Warszawa 02-668, Poland

Abstract

The study of crystal structure, elastic and magnetic properties of Nd1-xCaxMnO3 (x<=0.15) perovskites has been
carried out. The ferromagnetic component is shown to increase under hole doping and, simultaneously, the temperature of
orbital order-disorder phase transition decreases. The mechanism of concentrational transition from weak ferromagnetic
state (x=0) to ferromagnetic one (x>0.15) is discussed using two-phase model according to which the samples consist of weak
ferromagnetic and ferromagnetic phases exchange coupled at their boundary. It is found that interaction between different
magnetic phases leads to spin reorientation which takes place for 0.06<=x<=0.1 compounds around Teff~9 K. For the
Nd0.92Ca0.08MnO2.98 sample, the metamagnetic behaviour is revealed in the temperature range from 5 to 20 K. H vs.
T as well as T vs. x magnetic phase diagrams are proposed. The appearance of orientational transitions is explained on the
basis of magnetic !
analogue of Jahn-Teller effect taking into account that the magnetic moments of Nd ions are ordered parallel to the moments
of Mn ions in ferromagnetic phase, and opposite to the direction of weak ferromagnetics vector at T>Teff in weak
ferromagnetic phase.

 

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Related papers

Presentation: poster at E-MRS Fall Meeting 2003, Symposium D, by Vladimir A. Khomchenko
See On-line Journal of E-MRS Fall Meeting 2003

Submitted: 2003-07-25 16:54
Revised:   2009-06-08 12:55