Физика Низких Температур: Том 43, Выпуск 8 (Август 2017), c. 1219-1223    ( к оглавлению , назад )

Antiferromagnet-ferromagnet transition in La1–xSrxMn0.5Ni0.5O3 (0 ≤ x ≤ 0.2) ceramics

I.O. Troyanchuk1, D.V. Karpinsky1, M.V. Bushinsky1, V.A. Sirenko2, V.V. Sikolenko3,4, and A. Franz5

1Scientific-Practical Materials Research Centre NAS of Belarus, Minsk 220072, Belarus
E-mail: troyan@physics.by

2B. Verkin Institute for Low Temperature Physics and Engineering of National Academy of Sciences of Ukraine 47 Nauky Ave., Kharkov 61103, Ukraine

3Joint Institute for Nuclear Research, Dubna 141980, Russia

4REC “Functional nanomaterials” Immanuel Kant Baltic Federal University, 236041

5Helmholtz Zentrum Berlin, Hahn-Meitner-Platz 1, Berlin 14109, Germany

Received January 2, 2017

Аннотация

Ceramics samples of La1–xSrxMn0.5Ni0.5O3 (0 ≤ x ≤ 0.2) with perovskite structure have been studied by neutron diffraction method, magnetometry and magnetoresistance measurements. Structural data testify a partial order of the Ni and Mn ions in all the compounds in spite of chemical substitution of the La3+ ions by Sr2+ ones and an increase of the oxidation state of the Ni ions from 2+ towards to 3+ one. Magnetic structure of the compounds changes from ferromagnetic one (specific for the compound with x = 0) to antiferromagnetic (compounds with x ≥ 0.1) while the temperature of a transition into paramagnetic state remains about 270 K for all the samples. Magnetoresistance gradually decreases with temperature increase and strontium content. The results are discussed assuming nearly equal ferromagnetic and antiferromagnetic components of the superexchange interaction Ni2+–O–Mn4+ while the interaction between Ni3+ and Mn4 ions is considered to be strongly antiferromagnetic.

PACS: 61.05.F– Neutron diffraction and scattering;
PACS: 75.50.Dd Nonmetallic ferromagnetic materials;
PACS: 75.30.Et Exchange and superexchange interactions;
PACS: 75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects.

Ключевые слова: orbital ordering, exchange interaction, ferromagnetic state, manganites, perovskites.

Published online: June 26, 2017