Title :
Magnetoresistive and magnetic properties of RF-magnetron sputter deposited La-Ca,Sr-Mn-O films
Author :
Park, Seung-Iel ; Son, Ji-Hee ; Cho, Soung S. ; Kim, Chul S.
Author_Institution :
Dept. of Phys., Kookmin Univ., Seoul, South Korea
fDate :
9/1/2000 12:00:00 AM
Abstract :
Epitaxial and polycrystalline La-Ca,Sr-Mn-O thin films about 1000 Å thick were grown on LaAlO3(100), MgO(100) and SiO2/Si(100) substrates by RF magnetron sputtering. Changes in the resistivity and magnetoresistance of the films on LaAlO3 (100) substrate were investigated as the Ca and Sr ratio was varied. The crystal structure of the La-Ca,Sr-Mn-O films was determined to be orthorhombic perovskite. Lattice constants of the crystalline La 0.82Ca0.1Sr0.08MnO3 film were a0=5.466 Å, b0=5.392 Å, c0 =7.725 Å. When the amount of Sr was increased, the results of x-ray diffraction patterns showed no appreciable change of the lattice parameter. However, the semiconductor-metal transition temperature (TSC-M) of the epitaxial films on LaAlO3 (100) increased and the resistivity decreased as the amount of Sr was increased. For the epitaxial La0.82Ca0.1Sr0.08MnO3 film on LaAlO3, the temperature dependence of the resistivity under zero and 1.5 T applied fields showed that semiconductor-metal transition occurs at 246 K and the relative maximum magnetoresistance ratio was about 172% at 230 K
Keywords :
calcium compounds; colossal magnetoresistance; crystal structure; electrical resistivity; ferromagnetic materials; lanthanum compounds; lattice constants; magnetic epitaxial layers; magnetic thin films; metal-insulator transition; sputtered coatings; strontium compounds; 1.5 T; 100 A; 230 to 246 K; La0.82Ca0.1Sr0.08MnO3; LaAlO3; LaAlO3(100); MgO; MgO(100); RF-magnetron sputter deposited La-Ca-Sr-Mn-O films; Si; SiO2-Si; SiO2/Si(100); crystal structure; epitaxial La0.82Ca0.1Sr0.08MnO 3 film; epitaxial thin films; lattice constant; magnetic properties; magnetoresistance; magnetoresistive properties; orthorhombic perovskite; polycrystalline thin films; resistivity; semiconductor-metal transition temperature; substrates; temperature dependence; x-ray diffraction patterns; Conductivity; Crystallization; Lattices; Magnetic properties; Magnetoresistance; Radio frequency; Semiconductor films; Sputtering; Strontium; Substrates;
Journal_Title :
Magnetics, IEEE Transactions on
