Interface free energy and transition temperature of the square-lattice Ising antiferromagnet at finite magnetic field

1977 ◽  
Vol 27 (3) ◽  
pp. 261-266 ◽  
Author(s):  
E. M�ller-Hartmann ◽  
J. Zittartz
2001 ◽  
Vol 15 (24n25) ◽  
pp. 3156-3163
Author(s):  
YUNG M. HUH ◽  
D. K. FINNEMORE

Thermodynamic critical fields, Hc, have been measured for the La2-xSrxCuO4 family of superconductors in order to determine the changes in free energy of the system as the number of carriers is reduced. Magnetization vs. magnetic field curves are thermodynamically reversible over large portions of the H-T plane, so the free energy is well defined in these regions. Magnetization vs. field data are then fit to theoretical models to determine the thermodynamic critical fields. As the Sr concentration is changed from x=0.10 to 0.23, the values of Hc(T=0) goes through a maximum at optimum doping in a manner similar to the Tc vs x curve. The ratio of Hc(T = 0)/Tc also peaks in the region of x somewhat larger than optimum doping. As the value of x increases from underdoped to optimum doping, the cross-over temperature in the Msc vs. T curve, T*, approaches the transition temperature. In the overdoped regime there is no crossing in these Msc vs. T curves.


1989 ◽  
Vol 03 (07) ◽  
pp. 1119-1128
Author(s):  
K.Y. LIN ◽  
K.J. HSU

We have considered the Ising model on a layered square lattice where each layer has a different set of horizontal and vertical interactions. The free energy is determined exactly by the method of Pfaffian at two values of the magnetic field, H=0 and H=iπkT/2. The free energy at H=0 was first derived by Wolff et al. using the method of transfer matrix.


2011 ◽  
Vol 25 (26) ◽  
pp. 3435-3442
Author(s):  
XIAOYAN YAO

Wang–Landau algorithm of Monte Carlo simulation is performed to understand the thermodynamic and magnetic properties of antiferromagnetic Ising model on honeycomb lattice. The internal energy, specific heat, free energy and entropy are calculated to present the thermodynamic behavior. For magnetic property, the magnetization and magnetic susceptibility are discussed at different temperature upon different magnetic field. The antiferromagnetic order is confirmed to be the ground state of the system, and it can be destroyed by a large magnetic field.


2011 ◽  
Vol 44 (19) ◽  
pp. 7503-7507 ◽  
Author(s):  
Bryan McCulloch ◽  
Giuseppe Portale ◽  
Wim Bras ◽  
Rachel A. Segalman

2018 ◽  
Vol 115 (51) ◽  
pp. 12950-12955 ◽  
Author(s):  
Yuxing Yao ◽  
James T. Waters ◽  
Anna V. Shneidman ◽  
Jiaxi Cui ◽  
Xiaoguang Wang ◽  
...  

Dynamic functions of biological organisms often rely on arrays of actively deformable microstructures undergoing a nearly unlimited repertoire of predetermined and self-regulated reconfigurations and motions, most of which are difficult or not yet possible to achieve in synthetic systems. Here, we introduce stimuli-responsive microstructures based on liquid-crystalline elastomers (LCEs) that display a broad range of hierarchical, even mechanically unfavored deformation behaviors. By polymerizing molded prepolymer in patterned magnetic fields, we encode any desired uniform mesogen orientation into the resulting LCE microstructures, which is then read out upon heating above the nematic–isotropic transition temperature (TN–I) as a specific prescribed deformation, such as twisting, in- and out-of-plane tilting, stretching, or contraction. By further introducing light-responsive moieties, we demonstrate unique multifunctionality of the LCEs capable of three actuation modes: self-regulated bending toward the light source at T < TN–I, magnetic-field–encoded predetermined deformation at T > TN–I, and direction-dependent self-regulated motion toward the light at T > TN–I. We develop approaches to create patterned arrays of microstructures with encoded multiple area-specific deformation modes and show their functions in responsive release of cargo, image concealment, and light-controlled reflectivity. We foresee that this platform can be widely applied in switchable adhesion, information encryption, autonomous antennae, energy harvesting, soft robotics, and smart buildings.


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