National Yunlin University of Science and Technology

Lin-Hsiu Ye

Te-Ho Wu

Ching-Ming Lee

Alberto Canizo Cabrera

Jia-Mou Lee

Ying-Chuen Luo

Ming-Chi Weng

In A method for measuring a dimensionless coupling constant of a magnetic structure includes the following steps. A step of applying an external vertical magnetic field is performed for enabling magnetic moments of a RE-TM (Rare Earth-Transition metal) alloy magnetic layer of the magnetic structure to be vertical and saturated. A step of measuring a compensation temperature is performed when the sum of the magnetization of the RE-TM alloy magnetic layer is zero. A step of applying an external parallel magnetic field to the RE-TM alloy magnetic layer is performed. A step of adjusting the temperature of the magnetic structure to the compensation temperature and measuring a hysteresis loop of the magnetic structure under the external parallel magnetic field is performed, wherein the inverse of the slope of hysteresis loop is a dimensionless coupling constant.

Method of measuring dimensionless coupling constant of magnetic structure

A magnetic stack structure is disclosed. The magnetic stack structure includes two metal layers and a free layer sandwiched by the two metal layers. The thickness of the free layer is 1-30 nm. The thickness of the metal layers are 0.1-20 nm respectively.

Magnetic stack structure and manufacturing method thereof

A magnetic random access memory includes a substrate, a free layer and a spacer layer. The substrate and the free layer are made of a vertical anisotropy ferrimagentic thin film. The spacer layer is sandwiched between the substrate and the free layer and is made of an insulating layer. The method uses a modified Landau-Lifshitz-Gilbert equation to obtain a critical current value as a function of exchange coupling constant. The critical current value is predictable under several external magnetic fields being applied. When the exchange coupling constant is proportionally varied, the critical current value is reduced to a third of its original value under an optimum state.

Magnetic random access memory and method of reducing critical current of the same

A method for measuring hysteresis curves and anisotropic energy of magnetic memory units is disclosed. It comprises gradually applying different magnetic fields to a single-layer or a multilayer magnetic structure (such as a MRAM memory unit) by extra ordinary Hall effect, and recording the variation of the Hall voltage to obtain the hysteresis curve and anisotropic energy with specific instruments, and calculating the individual anisotropic energy value of the magnetic material of the single-layer or the multilayer magnetic structure.

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Yunlin, Taiwan

Lin-Hsiu Ye