ﻻ يوجد ملخص باللغة العربية
We have performed simultaneous measurements of magnetic chirality by using polarized neutrons and electric polarization along the b-axis of single crystals of YMn$^{4+}$(Mn$_{1-x}$Ga$_{x}$)$^{3+}$O$_{5}$ with $x=0.047$ and 0.12, in which nonmagnetic Ga-ions dilute Mn$^{3+}$ spins. The $x=0.047$ sample exhibits high-temperature incommensurate (HT-ICM), commensurate (CM), and low-temperature incommensurate (LT-ICM) magnetic phases in order of decreasing temperature, whereas the $x=0.12$ sample exhibits only HT-ICM and LT-ICM phases. Here, the CM and LT-ICM phases are ferroelectric and weak-ferroelectric, respectively. Measurements conducted under zero field heating after various field-cooling conditions evidence that the microscopic mechanisms of the spin-driven ferroelectricity in the CM and LT-ICM phases are different: the magnetic chirality of Mn$^{4+}$ cycloidal spins plays a dominant role in the LT-ICM phase, whereas the magnetic exchange striction by the Mn$^{4+}$-Mn$^{3+}$ chain plays a dominant role in the CM phase. The polarization of YMn$_{2}$O$_{5}$ flips upon CM to LT-ICM phase transition because the ferroelectricity driven by the magnetic chirality and the exchange striction provides opposite directions of polarization.
Detailed spin-wave spectra of magneto-electric LiNiPO4 have been measured by neutron scattering at low temperatures in the commensurate (C) antiferromagnetic (AF) phase with ordering temperature 20.8 K. An anomalous low-energy mode is observed at the
We report thermodynamic properties, magnetic ground state, and microscopic magnetic model of the spin-1 frustrated antiferromaget Li$_{2}$NiW$_{2}$O$_{8}$ showing successive transitions at $T_{rm N1}simeq 18$ K and $T_{rm N2}simeq 12.5$ K in zero fie
The vanadates VO$_2$ and V$_2$O$_3$ are prototypical examples of strongly correlated materials that exhibit a metal-insulator transition. While the phase transitions in these materials have been studied extensively, there is a limited understanding o
Temperature and field-dependent magnetization $M(H,T)$ measurements and neutron scattering study of a single crystal CeSb$_2$ are presented. Several anomalies in the magnetization curves have been confirmed at low magnetic field, i.e., 15.6 K, 12 K,
The compounds, PrCo9Si4 and NdCo9Si4, have been recently reported to exhibit first-order ferromagnetic transitions near 24 K. We have subjected this compound for further characterization by magnetization, heat-capacity and electrical resistivity meas