Magnetic ordering and granularity effects in La{sub 1-x}Ba{sub x}MnO{sub 3}
- Indian Institute of Technology Kanpur, Kanpur, 208016, (India)
- Brookhaven National Laboratory, Upton, New York 11973 (United States)
We report detailed measurements of the magnetic behavior of La{sub 1-x}Ba{sub x}MnO{sub 3} bulk samples over a wide range of composition (0{<=}x{<=}1), temperature (4.2-775 K), and magnetic field strength (1 G-50 kG). The end members of this series namely LaMnO{sub 3+{delta}} (with {delta}{>=}0) and BaMnO{sub 3} crystallize into pseudocubic perovskite and hexagonal lattices, respectively. The perovskite structure is stable for x{<=}0.35 while a phase separation into La{sub 0.65}Ba{sub 0.35}MnO{sub 3} and BaMnO{sub 3} occurs for x>0.35. The ordered moment on LaMnO{sub 3+{delta}} depends sensitively on the processing conditions and the lowest value of 0.006 {mu}{sub B} per Mn ion at 4.2 K is realized in the antiferromagnetic compound of {delta}=0. The complex magnetic behavior of BaMnO{sub 3} suggests antiferromagnetic ordering below {approx}150 K. The Ba-substituted compounds order ferromagnetically with a monotonic increase of T{sub C} and saturation magnetization M{sub s} with x<0.35. In the two-phase region, M{sub s} scales with the fraction of the ferromagnetic phase present in the sample. Magnetic granularity, superparamagnetism, and an effective medium approach for susceptibility of the two-phase mixture are discussed. (c) 2000 American Institute of Physics.
- OSTI ID:
- 20215428
- Journal Information:
- Journal of Applied Physics, Vol. 87, Issue 5; Other Information: PBD: 1 Mar 2000; ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
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