DAMPING DEPENDENCE OF REVERSAL MAGNETIC FIELD ON
CO-BASED NANO-FERROMAGNETIC WITH THERMAL
ACTIVATION
1)
Nadia Ananda Herianto, 2)Ferdy Semuel Rondonuwu, 2)Nur Aji Wibowo
1)
Pendidikan Fisika, Fakultas Sains dan Matematika, Universitas Kristen Satya Wacana 2)
Fisika, Fakultas Sains dan Matematika, Universitas Kristen Satya Wacana Jl. Diponegoro No.52-60, Salatiga (50711)
nadia.ananda.herianto@gmail.com
ABSTRACT
Currently, hard disk development has used HAMR technology that applies heat to perpendicular media until near Curie temperature, then cools it down to room temperature. The use of HAMR technology is significantly influence by Gilbert damping constants. Damping affects the magnetization reversal and coercivity field. Simulation is used to evaluate magnetization reversal by completing Landau-Lifshitz-Gilbert explicit equation. A strong ferromagnetic cobalt
based material with size 50×50×20 nm3 is used which parameters are anisotropy materials
3.51×106 erg/cm3, magnetic saturation 5697.5 G, exchange constant 1×10-7 erg/cm, and various
Gilbert damping from 0.09 to 0.5. To observe the thermal effect, two schemes are used which are Reduced Barrier Writing and Curie Point Writing. As a result, materials with high damping is able to reverse the magnetizations faster and reduce the energy barrier. Moreover, it can lower the minimum field to start the magnetizations reversal, threshold field, and probability rate. The heating near Curie temperature has succeded in reducing the reversal field to 1/10 compared to writing process in absence of thermal field.
