Temperature hysteresis of magnetic phase transitions in Tb1 − x Ce x Mn2O5 (x = 0, 0.20, 0.25)

Autor: S. V. Gavrilov, E. I. Golovenchits, I. A. Zobkalo, V. A. Sanina
Rok vydání: 2014
Předmět:
Zdroj: Physics of the Solid State. 56:51-56
ISSN: 1090-6460
1063-7834
Popis: The temperature evolution of the magnetic structure of multiferroics Tb1 − xCexMn2O5 (x = 0, 0.20, 0.25) has been investigated using the neutron scattering methods. It has been found that, despite the qualitative similarity of the magnetic states and the series of phase transitions for pure TbMn2O5 (TMO) and doped crystals Tb1 − xCexMn2O5 (TCMO, x = 0.20 and 0.25), there are significant differences in their properties. In contrast to TMO, where there are three magnetic phases, TCMO can include two magnetic phases that coexist in a wide temperature range and exhibit a rather wide temperature hysteresis. One of these phases with wave vector k1 = (0.5, 0, kz1), kz1 = 0.25, is commensurate and arises at temperatures below TN ∼ 39 K (for x = 0.2) and TN ∼ 38 K (x = 0.25). The second phase is incommensurate with wave vector k2 = (1/2, 0, kz2), kz2 = 0.256(2), and appears upon cooling at T = 21 K (x = 0.2) and T = 19 K (x = 0.25). Upon further cooling to 16 K, the component kz2 increases to 0.292(2) and then remains constant. The component kz1 increases to the value of 0.280(2) upon cooling in the range from 15 to 10 K and then remains constant down to 1.5 K. With an increase in the temperature, the components kz1 and kz2 undergo reverse changes to their initial values, but these changes occur at temperatures 7 K higher than those observed with a decrease in the temperature. For TMO, two phases also coexist, but the temperature hysteresis in this case is considerably smaller than for TCMO. This is explained by different densities of domain walls and different sizes of domains in pure and doped crystals.
Databáze: OpenAIRE
Externí odkaz: