Chemical and physical pressure effects in the A-site spinel antiferromagnets CoM.sub.2./sub.O.sub.4./sub. (M = Al, Co, and Rh)

0538257 - FZÚ 2021 RIV GB eng J - Journal Article
Naka, T. - Valenta, J. - Kaštil, Jiří - Míšek, Martin - Prchal, J. - Sechovský, V. - Abe, H. - Nakane, T. - Nakayama, M. - Uchikoshi, T.
Chemical and physical pressure effects in the A-site spinel antiferromagnets CoM₂O₄ (M = Al, Co, and Rh).
Materials Research Express. Roč. 7, č. 5 (2020), s. 1-14, č. článku 056105. E-ISSN 2053-1591
R&D Projects: GA MŠMT(CZ) LM2018096
Institutional support: RVO:68378271
Keywords : magnetic transition * pressure effects * diamond lattice * antiferromagnetism * magnetic frustration
OECD category: Condensed matter physics (including formerly solid state physics, supercond.)
Impact factor: 1.620, year: 2020
Method of publishing: Open access

Magnetic phase transitions under high pressure are reported for the diamond lattice antiferromagnet Co3-xRhxO4 in the range of 0 <= x <= 2.0, which is an isostructural S = 3/2 system for the well-known frustrated antiferromagnet CoAl2O4. In the Co3-xRhxO4 system, magnetic and specific-heat measurements at ambient pressure revealed that a second-order antiferromagnetic transition occurred at the Neel temperature (T-N) which exhibits a nonmonotonic x-variation. The physical pressure variations of T-N were determined by ac-calorimetry under hydrostatic pressures up to p = 2.6 GPa for Co2RhO4 and CoRh2O4. The rates of change of T-N with pressure (i.e., the pressure coefficients), 1.93 and 1.61 K GPa(-1), respectively, were comparable to those for CoAl2O4 and Co3O4, respectively. The pressure coefficients of magnetic ordering temperature for these A-site spinel compounds were considerably larger than those for other spinel and iron-garnet compounds which follow the empirical '10/3 law'. Simple analysis of the chemical and physical pressure coefficients of T-N revealed that T-N depended on both the lattice volume and the oxygen positional parameter u.
Permanent Link: http://hdl.handle.net/11104/0316096