91 research outputs found
Thermal Expansion of Forsterite, Mg2SiO4 : 1. Measurements
Thermal expansion of forsterite, Mg2SiO4, is measured up to 1,600 K by the dilatometric method. The present results of volume thermal expansion Yv is 3.20 percent from 300 to 1,200 K and expansion coefficient αv is 40.5 × 10-6 K-1 at 1,200 K. They are close to those of a natural olivine (Suzuki, 1976), but are 4.4 and 11 percent smaller as compared with those reported in the former paper (Suzuki et al., 1984). The Yv and αv of forsterite are 5.00 percent and 46.7 × 10-6 K-1 respectively, at 1,600 K
Antiferromagnetic order driven by the molecular orbital order of C in --tetra----(dimethylamino)--ethylene--C
We have studied the ground state of a fullerene--based magnet, the
--phase tetra----(dimethylamino)--ethylene--C
(--TDAE--C), by electron spin resonance (ESR) and magnetic
torque measurements. Below T K, non--paramagnetic field dependent
resonances with a finite excitation gap (1.7 GHz) are observed along the
--axis. Strong enhancement in their intensity as temperature is decreased is
inconsistent with excitation from a singlet state, which had been proposed for
the --phase ground state. Below T, non--quadratic field dependence
of magnetic torque signal is also observed in contrast to quadratic field
dependence in the paramagnetic phase. The angle--dependent torque signals below
T indicate the existence of an anisotropy of the bulk magnetization. From
both experiments, we propose an antiferromagnetic ground state driven by the
cooperative orientational ordering of C in the
--TDAE--C.Comment: 4 pages, 3 figure
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