Inhomogeneous Magnetic Structures of La0.7Ca0.3MnO3 Investigated by ESR and Magnetization Measurements

1999 ◽  
Vol 602 ◽  
Author(s):  
Keon Woo Joh ◽  
Chang Hoon Lee ◽  
Cheol Eui Lee ◽  
Yoon Hee Jeong ◽  
C. S. Hong ◽  
...  
Keyword(s):  
Electron Spin Resonance ◽  
Quantitative Analysis ◽  
Long Range ◽  
Electron Spin ◽  
Range Order ◽  
The Other ◽  
Long Range Order ◽  
Magnetization Measurements ◽  
Magnetic Structures ◽  
Spin Resonance

AbstractComprehensive measurements of electron spin resonance and magnetization of La0.7Ca0.3MnO3 in the ferromagnetic as well as paramagnetic phases were carried out. From the quantitative analysis of the ESR signal, attributed to itinerant spins and localized spins in the bottleneck regime, evidences for the inhomogeneous nature of both phases, consisting of clusters of one phase embedded in the other, were found. It is suggested that the microscopic local magnetic structures above and below Tc are qualitatively similar except that the phase below Tc carries long range order.

ABSENCE OF PHASE TRANSITIONS ON TREE STRUCTURES

1993 ◽  
Vol 07 (29n30) ◽  
pp. 1947-1950 ◽  
Author(s):  
RAFFAELLA BURIONI ◽  
DAVIDE CASSI
Keyword(s):  
Long Range ◽  
Nearest Neighbor ◽  
Linear Chain ◽  
Mean Field ◽  
Range Order ◽  
The Other ◽  
Long Range Order ◽  
Field Phase ◽  
Tree Structures ◽  
Bethe Lattices

We rigorously prove that the correlation functions of any statistical model having a compact transitive symmetry group and nearest-neighbor interactions on any tree structure are equal to the corresponding ones on a linear chain. The exponential decay of the latter implies the absence of long-range order on any tree. On the other hand, for trees with exponential growth such as Bethe lattices, one can show the existence of a particular kind of mean field phase transition without long-range order.

FERROMAGNETIC TDAE-C60 VERSUS PARAMAGNETIC TDAE-C70: FARADEY BALANCE AND ESR STUDY

1992 ◽  
Vol 06 (23n24) ◽  
pp. 3953-3958 ◽  
Author(s):  
Kazuyoshi Tanaka ◽  
Anvar A. Zakhidov ◽  
Kazunari Yoshizawa ◽  
Kenji Okahara ◽  
Tokio Yamabe ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Electron Spin Resonance ◽  
Electron Spin ◽  
Fullerene Molecule ◽  
The Other ◽  
Temperature Range ◽  
Type Transition ◽  
Other Hand ◽  
Spin Resonance ◽  
Ordered State

Magnetic properties of C 60 and C 70 complexes with tetrakis(dimethylamino)ethylene (TDAE) have been studied based on the measurements of the Faraday-balance magnetization and the electron spin resonance (ESR). It has been found that both TDAE- C 60 and TDAE- C 70 possess about one radical spin per fullerene molecule. TDAE- C 60 has been confirmed to show ferromagnetic-type transition at Tc=16.7–17.5 K . Appearance of a new broad and intense ESR signal below Tc of TDAE- C 60 suggests that the radical spins in the magnetically ordered state rather localize on each C 60 molecule and are ferromagnetically correlated. On the other hand, TDAE- C 70 does not show ferromagnetism in all the temperature range down to 4.5K.

Electron spin resonance analysis of magnetic structures in La2/3Ca1/3MnO3

2005 ◽  
Vol 293 (2) ◽  
pp. 782-786 ◽  
Author(s):  
Tao Ding ◽  
Weitao Zheng ◽  
Jianfeng Zang ◽  
Hongwei Tian ◽  
Bing Zheng ◽  
...  
Keyword(s):  
Electron Spin Resonance ◽  
Electron Spin ◽  
Magnetic Structures ◽  
Resonance Analysis ◽  
Spin Resonance
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