Magnetoresistive sensor can be widely used in modem transportation field, such as the vehicle positioning and navigation system, vehicle detection system, and intelligent transportation system. In order to improve the...Magnetoresistive sensor can be widely used in modem transportation field, such as the vehicle positioning and navigation system, vehicle detection system, and intelligent transportation system. In order to improve the efficiency of magnetoresistive sensor, we synthesized Lao.sSro.2MnO3 polycrystalline bulks at different sintering temperatures and investigated their DC and AC transport properties in this work. As a result, all samples showed insulator-metal （I-M） phase transition, and the transition temperature （TI-M） shifted to higher temperature with the increase of sintering temperature. The TI-M measured at different AC frequencies was smaller than that measured at DC condition, which implied that the I-M phase transition was suppressed at AC frequencies. The resistivity mea- sured at high AC frequencies was larger than that measured at low AC frequencies, which could be attributed to the change of the magnetic penetration depth （6）. However, the room-temperature AC-magnetoresistance （MR） at low frequencies was much larger than that at high frequencies and room-temperature DC-MR. These findings demon- strate that reducing the AC frequency is an effective way for enhancing the room-temperature MR, which can be used to promote the efficiency of magnetoresistive sensor.展开更多
基金supported by the National Magnetic Confinement Fusion Science Program (No. 2011GB112001)Program of International S&T Cooperation (No. 2013DFA51050)+3 种基金the National Natural Science Foundation of China (Nos. 51002125, 11104224, 11004162, and 51271155)the Research Fund for the Doctoral Program of Higher Education of China (No. 20110184120029)the Fundamental Research Funds for the Central Universities (Nos. 2682013ZT16, SWJTU12CX18, SWJTU11ZT31, 2682013CX004, and SWJTU11BR063)the Science Foundation of Sichuan Province (Nos. 2011JY0031 and 2011JY0130)
文摘Magnetoresistive sensor can be widely used in modem transportation field, such as the vehicle positioning and navigation system, vehicle detection system, and intelligent transportation system. In order to improve the efficiency of magnetoresistive sensor, we synthesized Lao.sSro.2MnO3 polycrystalline bulks at different sintering temperatures and investigated their DC and AC transport properties in this work. As a result, all samples showed insulator-metal （I-M） phase transition, and the transition temperature （TI-M） shifted to higher temperature with the increase of sintering temperature. The TI-M measured at different AC frequencies was smaller than that measured at DC condition, which implied that the I-M phase transition was suppressed at AC frequencies. The resistivity mea- sured at high AC frequencies was larger than that measured at low AC frequencies, which could be attributed to the change of the magnetic penetration depth （6）. However, the room-temperature AC-magnetoresistance （MR） at low frequencies was much larger than that at high frequencies and room-temperature DC-MR. These findings demon- strate that reducing the AC frequency is an effective way for enhancing the room-temperature MR, which can be used to promote the efficiency of magnetoresistive sensor.
