J.X.Zhang1)
,
K. Tamarat2) and B. Dubois2) 1) Schoolof Material Science & Engineering
,
Hebei University of Technology
,
Tianjin 300130
,
China2) ISMCM LISSMA
,
St.Ouen 93407
,
France
金属学报(英文版)
Thethermal induced γ εmartensitic transformation in a Fe 31 6 Mn 6 5 Si ( wt% ) alloy wasstudied by meansof X ray diffraction throughtwothermalcyclesin the83 480 Ktem perature range.Itisshownthatduringcoolingtheγ→εtransformationterminatesnotat TγNbutatalowertemperatureandtheγphaseexhibitsstrongstabilityevencoolingto83 K;like wise,εmartensiteis noticeably stable even heating up to 480 K. Atthe temperature about 275 K, an anomalousdecreaseintheintensityofthe(200)γreflections wasobserved on heat ing, whereasthe(101)εreflectionsshow ageneralvariationinintensity.Itisconsideredthat theabnormalphenomenonis probably related tothe magnetictransition of the γphase fromantiferromagnetism to paramagnetism .
关键词:
Fe Mn
,
null
,
null
,
null
J.P.Renard Institut d'Electronique Fondamentale
,
Batiment 220
,
CNRS URA 22
,
Université Paris-Sud
,
91405
,
Orsay-Cedex
,
France
材料科学技术（英文）
Magnetic multilayers are artificially structured materials made of ultrathin films of two different mate- rials,alternately ferromagnetic and non-ferromagnetic.They exhibit new magnetic properties differ- ent from those of bulk materials.We review the magnetic properties of metallic magnetic multilayers and focus on interface magnetic anisotropy,giant magnetoresistance and interlayer couplings,which are of great promise for applications to high density magnetic storage.
关键词:
magnetic multilayer
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null
,
null
T.S.Ke (Tingsui GE)(Lab. of Internal Friction and Defects in Solids
,
Institute of Solid State Physics
,
Chinese Academy of Sciences
,
Hefei 230031
,
China)
材料科学技术（英文）
In the seventies some scientific workers from France and ltaly suggested that the grain boundary internal friction peak (named the Ke peak in the literature) widely accepted as a grain bound ary process, is originated from the motion of lattice dislocations. Since this problem is one of fundamental importance, this controversy has drawn much international attention. Started from 1982, the Hefei research group made a critical analysis of the large amount of literature concerning this problem and performed a series of crucial experiments to clarify the controversy It is concluded that the irrelevant evidence suggested by the controverters comes from the farfetched interpretation and the mis-identification of the internal friction peaks appeared under various experimental conditions and different states of the specimens.
关键词:
Journal of Mathematical Chemistry
We start from a classical statistical-mechanical theory for the internal energy in terms of three-and four-body correlation functions g(3) and g(4) for homogeneous atomic liquids like argon, with assumed central pair interactions phi(r(ij)). The importance of constructing the partition function (pf) as spatial integrals over g(3), g(4) and phi is stressed, together with some basic thermodynamic consequences of such a pf. A second classical example taken for two-body interactions is the so-called one-component plasma in two dimensions, for a particular coupling strength treated by Alastuey and Jancovici (J Phys (France) 42:1, 1981) and by Fantoni and Tellez (J Stat Phys 133: 449, 2008). Again thermodynamic consequences provide a particular focus. Then quantum-mechanical assemblies are treated, again with separable many-body interactions. The example chosen is that of an N-body inhomogeneous extended system generated by a one-body potential energy V(r). The focus here is on the diagonal element of the canonical density matrix: the so-called Slater sum S(r, beta), related to the pf by pf(beta) = integral S(r, beta) d (r) over right arrow, beta = (k(B)T)(-1). The Slater sum S(r, beta) can be related exactly, via a partial differential equation, to the one-body potential V(r), for specific choices of V which are cited. The work of Green (J Chem Phys 18: 1123, 1950), is referred to for a generalization, but now perturbative, to two-body forces. Finally, to avoid perturbation series, the work concludes with some proposals to allow the treatment of extended assemblies in which regions of long-range ordered magnetism exist in the phase diagram. One of us (Z. D. Z.) has recently proposed a putative pf for a three-dimensional (3D) Ising model, based on two, as yet unproved, conjectures and has pointed out some important thermodynamic consequences of this pf. It would obviously be of considerable interest if such a pf, together with conjectures, could be rigorously proved.
关键词:
Statistical-mechanical models;Many-body interactions;Partition;functions;Thermodynamic consequences;orthorhombic ising lattices;one-component plasma;recent conjectured;solution;bare coulomb field;slater sum;pair potentials;renormalization group;critical exponents;magnetic equation;critical-point
