A Monte-Carlo simulation on phase transitions in ferroelectromagnets (FEMs) in which a weak antiferromagnetic ordering occurs at the Neel point TN far below the ferroelectric ordering point TE was performed. It is rev...A Monte-Carlo simulation on phase transitions in ferroelectromagnets (FEMs) in which a weak antiferromagnetic ordering occurs at the Neel point TN far below the ferroelectric ordering point TE was performed. It is revealed that an intrinsic coupling between spins and electric-dipoles (mp-coupling) does result in a weak ferromagnetic transition from the paramagnetic state at a temperature far above TN, as long as the coupling is strong enough. The magnetoelectric properties as a function of temperature, mp-coupling strength and external electric and magnetic fields were investigated. A mean-field calculation based on the Heisenberg model was performed and a rough consistency between the simulated and calculated ferromagnetic transitions was shown.展开更多
Besides the two phase transitions known in ferroelectromagnets, an additional transition was observed experimentally in Pb(Fe1/2Nb1/2)O3 and the possible mechanism was explored. The magnetic moment shows that anomalou...Besides the two phase transitions known in ferroelectromagnets, an additional transition was observed experimentally in Pb(Fe1/2Nb1/2)O3 and the possible mechanism was explored. The magnetic moment shows that anomalous increases when the temperature goes down away from the Néel temperature of 20-30 K. The existence of the hysteresis verifies the weak ferromagnetic property. This additional phase transition is considered to originate from the magnetoelectric coupling between the ferroelectric and antiferromagnetic orders in this compound. From the M?ssbauer parameter analysis, it is confirmed that the hybridization of the O 2p, Fe 3d and Nb 4d electron states makes the realization of magnetoelectric coupling possible.展开更多
基金This project was financially supported by the National Natural Science Foundation of China (Nos. 50332020, 10021001, 10474039) and the National Key Project for Basic Researches of China (No. 2002CB613303).
文摘A Monte-Carlo simulation on phase transitions in ferroelectromagnets (FEMs) in which a weak antiferromagnetic ordering occurs at the Neel point TN far below the ferroelectric ordering point TE was performed. It is revealed that an intrinsic coupling between spins and electric-dipoles (mp-coupling) does result in a weak ferromagnetic transition from the paramagnetic state at a temperature far above TN, as long as the coupling is strong enough. The magnetoelectric properties as a function of temperature, mp-coupling strength and external electric and magnetic fields were investigated. A mean-field calculation based on the Heisenberg model was performed and a rough consistency between the simulated and calculated ferromagnetic transitions was shown.
基金Projects(50572038 10374048) supported by the National Natural Science Foundation of China
文摘Besides the two phase transitions known in ferroelectromagnets, an additional transition was observed experimentally in Pb(Fe1/2Nb1/2)O3 and the possible mechanism was explored. The magnetic moment shows that anomalous increases when the temperature goes down away from the Néel temperature of 20-30 K. The existence of the hysteresis verifies the weak ferromagnetic property. This additional phase transition is considered to originate from the magnetoelectric coupling between the ferroelectric and antiferromagnetic orders in this compound. From the M?ssbauer parameter analysis, it is confirmed that the hybridization of the O 2p, Fe 3d and Nb 4d electron states makes the realization of magnetoelectric coupling possible.
