%0 Journal Article
%T Giant Magnetoresistance Effect in La-Pb-Mn-O Polycrystalline Bulk Materials<br>多晶La-Pb-Mn-O体材料的巨磁电阻效应
%A Tsukamoto Koichi
%A Yanagisawa Takeshi
%A Ito Toshimitsu
%A Higuchi Noboru
%A Okada Yasumasa
%A Okutomi Mamoru
%A ZHU Xiang-Rong
%A SHEN Hong-Lie
%A SHEN Qin-Wo
%A ZOU Shi-Chang
%A Tsukamoto Koichi
%A Yanagisawa Takeshi
%A Ito Toshimitsu
%A Higuchi Noboru
%A Okada Yasumasa
%A Okutomi Mamoru
%A <br>祝向荣
%A 沈鸿烈
%A 沈勤我
%A 邹世昌
%A TsukamotoKoichi
%A YanagisawaTakeshi
%A ItoToshimitsu
%A HiguchiNoboru
%A OkadaYasumasa
%A Okutomi Mamoru
%J 无机材料学报
%D 1999
%I Science Press
%X Cubic polycrystalline bulk materials of L-aPb-Mn-O were prepared by solid state reaction method. Magnetic measurements indicated that the samples are ferromagnetic, and TC is 257K. Magnetotransport measurements showed that the metal-semiconductor transition temperature (TP) of the samples is 251K, and near Tp the giant magnetoresistance (GMR) peak vaues reach 72% and 85% under 5T and 13T magnetic field, respectively. It was noticed that the samples present GMR effect over a wide temperature range from 77K to room temperature. The GMR effect is related to the behavior of the spin polaron, which is affected by both temperature and applied field. Besides the influence of the spin polaron, the GMR peak effect near Tp is also ascribed to the strong decline of spin-disorder scattering of carriers caused by the applied field. Furthermore, the GMR effect over the whole measured temperature, especially at low temperatures far below TP, is also resulted from the spin-dependent scattering of carriers near grain boundary associated with the polycrystallinity of the samples. In addition, the inhibition of the spin-polarized intergrain tunneling at TP leads to the disappearance of the low-field GMR effect caused by the Hund exchange.
%K GMR
%K metal-semiconductor transition temperature
%K polycrystalline<br>巨磁电阻
%K 金属
%K 半导体
%K 稀土锰氧化物
%K 铁磁材料
%U http://www.alljournals.cn/get_abstract_url.aspx?pcid=5B3AB970F71A803DEACDC0559115BFCF0A068CD97DD29835&cid=84529CA2B2E519AC&jid=ABC0063016AF57E1C73EF43C8D2212BD&aid=894D70E4A6F117E77F14FFA669A6FC4E&yid=B914830F5B1D1078&vid=F3583C8E78166B9E&iid=B31275AF3241DB2D&sid=BD77137A0285B6FF&eid=753F7A67351FADCC&journal_id=1000-324X&journal_name=无机材料学报&referenced_num=0&reference_num=16