The ferromagnetic antiresonance （FMAR） phenomenon, i.e., the minimum of the microwave absorption, in polycrystalline La0.49Sr0.51MnO3 is observed near Curie temperature TC = 282 K. Temperature-dependences of magneti...The ferromagnetic antiresonance （FMAR） phenomenon, i.e., the minimum of the microwave absorption, in polycrystalline La0.49Sr0.51MnO3 is observed near Curie temperature TC = 282 K. Temperature-dependences of magnetization μ0M are obtained from the FMAR. The results show that as μ0H = 0, by fitting the scaling law M ∝ （TC -T）^β to temperature-dependences of μ0M at the different microwave frequencies, it yields TC=281.2 K and β = 0.47. However, temperature-dependences of μ0M under different μ0H are not in agreement with the scaling law. Due to FMAR, about 40% giant microwave magneto-impedance at 11.9 GHz can occur under a low field μ0H = 0.03 T.展开更多
For a one-dimensional barrier of arbitrary shape,an expression of the dwell time of tunneling particles has been obtained by subdividing it into infinitesimal rectangular barrier elements and then summing the dwell ti...For a one-dimensional barrier of arbitrary shape,an expression of the dwell time of tunneling particles has been obtained by subdividing it into infinitesimal rectangular barrier elements and then summing the dwell times spent by particles inside the barrier elements,and the dwell times in a parabolic potential barrier were calculated.The results show that the dwell times are almost independent of the barrier width as it is greater than a characteristic width Wc.This can be ascribed that in the width range beyond Wc,the tunneling probabilities through the barrier elements are very small,thus the times taken to tunnel through them make little contribution to the summation of the dwell times in all the barrier elements.展开更多
文摘The ferromagnetic antiresonance （FMAR） phenomenon, i.e., the minimum of the microwave absorption, in polycrystalline La0.49Sr0.51MnO3 is observed near Curie temperature TC = 282 K. Temperature-dependences of magnetization μ0M are obtained from the FMAR. The results show that as μ0H = 0, by fitting the scaling law M ∝ （TC -T）^β to temperature-dependences of μ0M at the different microwave frequencies, it yields TC=281.2 K and β = 0.47. However, temperature-dependences of μ0M under different μ0H are not in agreement with the scaling law. Due to FMAR, about 40% giant microwave magneto-impedance at 11.9 GHz can occur under a low field μ0H = 0.03 T.
基金Supported by Shenzhen Scince-Technology Programs。
文摘For a one-dimensional barrier of arbitrary shape,an expression of the dwell time of tunneling particles has been obtained by subdividing it into infinitesimal rectangular barrier elements and then summing the dwell times spent by particles inside the barrier elements,and the dwell times in a parabolic potential barrier were calculated.The results show that the dwell times are almost independent of the barrier width as it is greater than a characteristic width Wc.This can be ascribed that in the width range beyond Wc,the tunneling probabilities through the barrier elements are very small,thus the times taken to tunnel through them make little contribution to the summation of the dwell times in all the barrier elements.
