scholarly journals Increase of Magnetic Transition Temperatures by Reduction of Local Disorder for Perovskite Manganites

2002 ◽  
Vol 718 ◽  
Author(s):  
B. Dabrowski ◽  
O. Chmaissem ◽  
J. Mais ◽  
S. Kolesnik ◽  
J.D. Jorgensen ◽  
...  
Keyword(s):  
Oxygen Content ◽  
Phase Stability ◽  
Magnetic Transition ◽  
Structural Disorder ◽  
Tolerance Factor ◽  
Perovskite Manganites ◽  
Transition Temperatures ◽  
Local Disorder

AbstractWe report the synthesis of Sr1-xCaxMnO3 and La0.5Ba0.5MnO3 perovskites over extended cation and oxygen composition ranges and describe the dependence of their phase stability on the tolerance factor t = t(x,T,σ) that is a function of composition, temperature, and oxygen content. We show that magnetic transition temperatures depend strongly on the tolerance factor and charge disorder while dependence on the structural disorder is less important. By reducing charge and structural disorder we have significantly increased the Curie and Neel temperatures for perovskite manganites.

scholarly journals Annealing Effect on Martensitic Transformation and Magneto-Structural Properties of Ni-Mn-In Melt Spun Ribbons

2009 ◽  
Vol 635 ◽  
pp. 81-87 ◽  
Author(s):  
T. Sánchez ◽  
José Luis Sánchez Llamazares ◽  
B. Hernando ◽  
J.D. Santos ◽  
M.L. Sánchez ◽  
...  
Keyword(s):  
Phase Transition ◽  
Structural Properties ◽  
Magnetic Transition ◽  
Structural Phase ◽  
Hysteresis Loops ◽  
Transition Temperatures ◽  
Average Chemical Composition ◽  
Saturation Field ◽  
Existence Region ◽  
Phase Transition Temperatures

We report the effect of a short-time vacuum annealing (1073 K during 10 minutes) on structural phase transition temperatures and magneto-structural properties of as-quenched ribbons of the Heusler alloy Ni50.6Mn34.5In14.9. This alloy crystallizes in a single phase cubic B2-type austenite with a Curie point of TCA=284 K that with the lowering in temperature transforms into a martensite with TCM185 K. The direct and reverse martensitic phase transition temperatures were MS=257 K, Mf = 221 K, AS = 239 K, and Af = 266 K. After annealing austenite shows the highly ordered L21-type structure while the average chemical composition as well as the structural and magnetic transition temperatures were shifted to Ni50.2Mn34.3In15.5 and MS = 253 K, Mf = 238 K, AS = 257 K, Af = 265 K, ΔT = 13 K, TCA = 299 K and TCM207 K. In the annealed samples the magnetization changes associated to the magnetic and structural transitions are more abrupt and magnetization isotherms in both the austenitic and martensitic existence region show higher initial magnetic susceptibility and faster approach to saturation. Field-cooled hysteresis loops at 10 K were shifted along the negative H-axis for both samples, but a significant anomaly was evident on the left side of the hysteresis loop for as-quenched ribbons.

Pressure effect on magnetic transition temperatures of Mn3Ga1−xMxC (M=Zn,Sn)

1990 ◽  
Vol 67 (9) ◽  
pp. 4824-4826 ◽  
Author(s):  
T. Kanomata ◽  
T. Kawashima ◽  
H. Yoshida ◽  
T. Kaneko
Keyword(s):  
Pressure Effect ◽  
Magnetic Transition ◽  
Transition Temperatures

Effect of tolerance factor and local distortion on magnetic properties of the perovskite manganites

1999 ◽  
Vol 75 (8) ◽  
pp. 1146-1148 ◽  
Author(s):  
J. P. Zhou ◽  
J. T. McDevitt ◽  
J. S. Zhou ◽  
H. Q. Yin ◽  
J. B. Goodenough ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Tolerance Factor ◽  
Perovskite Manganites ◽  
Local Distortion

Pressure Dependence of Magnetic Transition Temperatures and Lattice Parameter in an Antiferromagnetic Ordered Alloy Mn3Pt

1987 ◽  
Vol 56 (12) ◽  
pp. 4532-4539 ◽  
Author(s):  
Hiroyuki Yasui ◽  
Takejiro Kaneko ◽  
Hajime Yoshida ◽  
Shunya Abe ◽  
Kazuo Kamigaki ◽  
...  
Keyword(s):  
Pressure Dependence ◽  
Magnetic Transition ◽  
Lattice Parameter ◽  
Transition Temperatures
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