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Australian Institute for Innovative Materials - Papers

2014

Microstructure

Articles 1 - 2 of 2

Full-Text Articles in Engineering

Microscopic Model For Exchange Bias From Grain-Boundary Disorder In A Ferromagnet/Antiferromagnet Thin Film With A Nanocrystalline Microstructure, David L. Cortie, A G. Biternas, R W. Chantrell, Xiaolin Wang, Frank Klose Jan 2014

Microscopic Model For Exchange Bias From Grain-Boundary Disorder In A Ferromagnet/Antiferromagnet Thin Film With A Nanocrystalline Microstructure, David L. Cortie, A G. Biternas, R W. Chantrell, Xiaolin Wang, Frank Klose

Australian Institute for Innovative Materials - Papers

Monte Carlo spin simulations were coupled to a Voronoi microstructure-generator to predict the magnitude and behavior of exchange bias in a ferromagnet/antiferromagnet (AF) thin film bilayer with a nanocrystalline microstructure. Our model accounts for the effects of irregular grain-shapes, finite-sized particles, and the possible presence of local random-fields originating from the antiferromagnet's grain-boundary regions. As the grain-boundary represents a crystal-structure distortion, we model the local effect on the exchange constants in the Gaussian approximation which can cause regions resembling a spin glass confined to an unusual 2D topology. Although an ensemble of completely disconnected AF grains isolated by non-magnetic barriers …


Power-Law Relationship Between Critical Current Density, Microstructure, And The N-Value In Mgb2 Superconductor Wires, Ashkan Motaman, Shaon Barua, Dipak Patel, Minoru Maeda, Kookchae Cheong, Jung Ho Kim, S X. Dou, Md Shahriar Al Hossain Jan 2014

Power-Law Relationship Between Critical Current Density, Microstructure, And The N-Value In Mgb2 Superconductor Wires, Ashkan Motaman, Shaon Barua, Dipak Patel, Minoru Maeda, Kookchae Cheong, Jung Ho Kim, S X. Dou, Md Shahriar Al Hossain

Australian Institute for Innovative Materials - Papers

Dissipation-free MgB2 superconducting wires are valuable in terms of practical applications. Herein, we have found a strong correlation between critical current density (J c ) and the n-value extracted from the electric field versus current density characteristic. The power-law relationship (m) between the J c and the n-value, n∝Jmc , represents a critical index which is strongly dependent on operating temperatures.