La_(0.3)Ca_(0.7)Mn_(1-x)W_xO_3(x=0.04,0.08,0.12)体系的电子自旋共振谱研究  

RESEARCH ON ELECTRON SPIN RESONANCE OF La_(0.3)Ca_(0.7)Mn_(1-x)W_xO_3(x=0.04,0.08,0.12) SYSTEM

作　　者：刘宁[1] 严国清[1] 郭焕银[1] 

机构地区：[1]宿州学院材料研究室

出　　处：《低温物理学报》2007年第2期81-85,共5页Low Temperature Physical Letters

基　　金：国家自然科学基金重点项目(项目编号:19934003);国家重点基础研究发展规划项目(项目编号:001CB610604);安徽省教育厅自然科学研究基金(项目编号:2006KJ266B)资助的课题~~

摘　　要：用固相反应法制备了La0.3Ca0.7Mn（1-x）WxO3（x=0.04,0.08,0.12）多晶材料,测量了样品的p～T曲线及ESR谱,对ESR谱的归一化强度和线宽进行了研究.结果表明：当x≤0.08时,ρ～T曲线出现弯折点,体系出现电荷有序（CO）相,体系随温度降低发生顺磁（PM）-电荷有序（CO）-反铁磁（AFM）变化;当x=0.12时,ρ～T曲线没有出现弯折点,CO相融化,自旋序主要是顺磁（PM）,但存在CO相的残留.x≤0.08样品的线宽在高于Tco的温区几乎不随温度变化,体系处在顺磁态,铁磁关联较弱;在低于Tco的温区,电子的局域化程度增强,线宽随温度的降低而增加.The polycrystalline material La0.3Ca0.7Mn（1-x）WxO3（x=0.04,0.08,0.12） was prepared by the solid-state reaction method, p ~ T curves and ESR spectra of the samples were measured, and the normalized intensity and the linewidth of ESR spectra are studied. The results show that： When x ≤ 0.08, the ρ - T curves exhibit an inflection point, the system exhibits charge-ordering（CO） phase, and the spin order exhibits paramagnetism （PM） -charge ordering （ CO ） -antiferromagnetism （AFM） transition with temperature decreasing; when x = 0.12, the ρ- T curve doesn＇ t exhibit the inflection point, the CO phase melts, the spin ordering is mainly paramagnetism （PM）, and the ferromagnetic correlation strengthens at low temperature. For the samples of x ≤0.08, on the temperature range above Tco, the linewidth almost doesn＇ t change, the system is in paramagnetic state, and the ferromagnetic correlation is comparatively weak; on the temperature range below Tco, the ferromagnetic correlation of the system strengthens, and the linewidth increases with temperature decreasing.

关 键 词：电荷序 自旋序 融化 归一化强度 线宽 

分 类 号：O482[理学—固体物理]