Magnetic and structural properties of pure and Cr-doped haematite:α-Fe_(2-x)Cr_(x)O_(3)(0≤x≤1)  

作　　者：Arvind YOGI Dinesh VARSHNEY 

机构地区：[1]Materials Science Laboratory,School of Physics,Vigyan Bhawan,Devi Ahilya University,Khandwa Road Campus,Indore 452001,India [2]School of Physics,Indian Institute of Science Education and Research,Thiruvananthapuram 695016,India

出　　处：《Journal of Advanced Ceramics》2013年第4期360-369,共10页先进陶瓷（英文）

基　　金：Authors are thankful to UGC New Delhi for financial assistance

摘　　要：Solid-state ceramic technique route is used for synthesizing Cr-doped haematiteaα-Fe_(2-x)Cr_(x)O_(3)(x=0,0.125,0.50 and 1)samples.Single phase and corundum(Al2O_(3))type structure is revealed from the X-ray diffraction(XRD)patterns.The Raman spectra ofαa-Fe_(2-x)Cr_(x)O_(3)illustrate seven phonon modes.On substitution of Cr(x=0,0.125,0.50 and 1)at Fe site,all Raman active modes are shifted to higher wave numbers.The coercivity and remanence of Cr-doped haematites increase as x increases.The increased coercivity and remanence for Cr-doped samples can be attributed to their enhanced shape and magneto-crystalline anisotropy.The observed isomer shiftδdvalues from room-temperature Mössbauer data clearly show the presence of ferric(Fe^(3+))and Cr^(3+)ions illustrating strong ferromagnetic ordering up to x=0.125 inaα-Fe_(2-x)Cr_(x)O_(3)haematite and weak ferromagnetic ordering foraα-Fe2-xCrxO_(3)(x>0.125)haematites.

关 键 词：magnetic materials X-ray diffraction(XRD) Raman spectra Mössbauer spectroscopy 

分 类 号：O48[理学—固体物理]