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Full-Text Articles in Physics

Density Of Zeros On The Lee-Yang Circle Obtained From Magnetization Data Of A Two-Dimensional Ising Ferromagnet, Christian Binek Dec 1998

Density Of Zeros On The Lee-Yang Circle Obtained From Magnetization Data Of A Two-Dimensional Ising Ferromagnet, Christian Binek

Christian Binek Publications

In order to provide experimental access to the statistical theory of Lee and Yang [Phys. Rev. 87, 410 (1952)] the density function g(θ) of zeros on the Lee-Yang circle has been determined for the first time by analyzing isothermal magnetization data m(H) of the Ising ferromagnet FeCl2 in axial magnetic fields H at temperatures 34≤T≤99 K. The validity of our approach is demonstrated by the perfect agreement of magnetic specific heat data as calculated from g(θ) and m(H) via Maxwell's relation. Moreover, the correct in-plane exchange constant of FeCl2 emerges from the …


Polydispersivity Of Non-Critical Field-Induced Fluctuations In Febr2, Christian Binek May 1998

Polydispersivity Of Non-Critical Field-Induced Fluctuations In Febr2, Christian Binek

Christian Binek Publications

The field and temperature dependence of the complex low-frequency susceptibility of the metamagnet FeBr2 exhibits large anomalies in the vicinity of the second-order phase boundary Hc(T). The low-frequency losses reflect polydispersive dynamics with a broad distribution of relaxation times peaking at τ ≈ 0.2 s. The dispersion, χ versus ƒ, is well described within Chamberlin's model of dynamically coupled domains. The heterogeneous glass-like response gives rise to the intuitive picture of a magnetic fluid of high viscosity.


Field-Induced Transverse Spin Ordering In Febr2, O. Petracie, Christian Binek, Wolfgang Kleemann, U. Neuhausen, H. Lueken May 1998

Field-Induced Transverse Spin Ordering In Febr2, O. Petracie, Christian Binek, Wolfgang Kleemann, U. Neuhausen, H. Lueken

Christian Binek Publications

Weak first-order phase transitions from axial to oblique spin ordering in FeBr2 are evidenced by superconducting quantum interference device magnetometry in axial fields H1(T) above the multicritical point, Hm=2.4 MA/m, Tm=4.6 K, and below the antiferro-to-paramagnetic phase line, Hc (T), in agreement with recent specific-heat data [H. Aruga Katori, K. Katsumata, and M. Katori, Phys. Rev. B 54, R9620 (1996)]. The ordering of the in-plane moments is probably due to nondiagonal coupling to the longitudinal ones, both of which increase discontinuously at H1 (T) only under …


Crossover From Pure Ising To Random-Exchange Dominated Behavior Of The Two-Dimensional Antiferromagnet Rb2Co1-XMgXF4, Christian Binek, Wolfgang Kleemann, David P. Belanger Apr 1998

Crossover From Pure Ising To Random-Exchange Dominated Behavior Of The Two-Dimensional Antiferromagnet Rb2Co1-XMgXF4, Christian Binek, Wolfgang Kleemann, David P. Belanger

Christian Binek Publications

The temperature dependence of the uniform susceptibility χ of diluted two-dimensional Ising antiferromagnets Rb2Co1-xMgxF4, 0<~xN(x), but also in relation to the “local” phase transition temperatures TN′ throughout the Griffiths regime, TN(x)<~TN′<~TN(0), a satisfactory quantitative description of χ vs T is deduced for any x above the percolation threshold. ©1998 The American Physical Society


Kinetics Of Random-Field Induced Domains In The Two-Dimensional Ising Antiferromagnet Rb2co0.85mg0.15f4, Christian Binek Jan 1998

Kinetics Of Random-Field Induced Domains In The Two-Dimensional Ising Antiferromagnet Rb2co0.85mg0.15f4, Christian Binek

Christian Binek Publications

The previous kinetics of the two-dimensional diluted Ising antiferromagnet Rb2Co0.85Mg0.15F4 is studied via the temporal relaxation of the field-induced magnetization after field cooling (FC) and zero-field cooling (ZFC), respectively, to T < TN = 75.2K. After FC different non-exponential decay laws indicate a crossover from domain reorientation to wall rearrangement at decreasing T. After ZFC rapidly saturating magnetization of naturally grown domain walls precedes the slow random-field-controlled disordering process.