We investigate the hysteretic behavior of the angular dependence of exchange bias for a series of polycrystalline NiFe/(FeMn)_(1-x)(MgO)_(x) bilayers with varying x.For x=0.025,the antiferromagnetic layer is of the la...We investigate the hysteretic behavior of the angular dependence of exchange bias for a series of polycrystalline NiFe/(FeMn)_(1-x)(MgO)_(x) bilayers with varying x.For x=0.025,the antiferromagnetic layer is of the largest degree of the fcc(111)preferred texture.At the same x,both the exchange field and blocking temperature acquire maximal values.In particular,the hysteretic behavior of the angular dependence between clockwise and counter-clockwise rotations shows minimal angular shift.These results can be explained in terms of the thermal activation model.展开更多
Co nanowire arrays have been fabricated into anodic aluminum oxide templates at 20C by dc electrodeposition.It is shown that Co nanowires fabricated at lower and higher growth voltages have a hexagonal close packing (...Co nanowire arrays have been fabricated into anodic aluminum oxide templates at 20C by dc electrodeposition.It is shown that Co nanowires fabricated at lower and higher growth voltages have a hexagonal close packing (hcp) structure with preferred [100] orientation along the nanowire axis and a face-centered cubic (fcc) structure with preferred [220] orientation,respectively.With increasing growth voltage,the room-temperature coercivity along the nanowire axis is enhanced gradually.For fcc Co nanowires,the coercivity increases monotonically with increasing temperature while for hcp Co nanowires,a minimal coercivity is obtained along both parallel-to-axis and perpendicular-to-axis orientations with the temperature rising from 50K to 390K.The abnormal temperature dependence of the coercivity can be attributed to the competition between the shape anisotropy and magnetocrystalline anisotropy as a function of temperature.展开更多
基金Supported by the Innovation Program of Shanghai Municipal Education Commission(No 10ZZ117)the Key Project of the Ministry of Education of China(No 210074).
文摘We investigate the hysteretic behavior of the angular dependence of exchange bias for a series of polycrystalline NiFe/(FeMn)_(1-x)(MgO)_(x) bilayers with varying x.For x=0.025,the antiferromagnetic layer is of the largest degree of the fcc(111)preferred texture.At the same x,both the exchange field and blocking temperature acquire maximal values.In particular,the hysteretic behavior of the angular dependence between clockwise and counter-clockwise rotations shows minimal angular shift.These results can be explained in terms of the thermal activation model.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11074112 and 10974032the National Basic Research Program of China under Grant Nos 2009CB929201 and 2010CB923401+1 种基金the Key Project of the Ministry of Education of China under Grant No 210074the Innovation Program of Shanghai Municipal Education Commission(No 10ZZ117).
文摘Co nanowire arrays have been fabricated into anodic aluminum oxide templates at 20C by dc electrodeposition.It is shown that Co nanowires fabricated at lower and higher growth voltages have a hexagonal close packing (hcp) structure with preferred [100] orientation along the nanowire axis and a face-centered cubic (fcc) structure with preferred [220] orientation,respectively.With increasing growth voltage,the room-temperature coercivity along the nanowire axis is enhanced gradually.For fcc Co nanowires,the coercivity increases monotonically with increasing temperature while for hcp Co nanowires,a minimal coercivity is obtained along both parallel-to-axis and perpendicular-to-axis orientations with the temperature rising from 50K to 390K.The abnormal temperature dependence of the coercivity can be attributed to the competition between the shape anisotropy and magnetocrystalline anisotropy as a function of temperature.
