Seagate Technology Incorporated

Roy William Chantrell

Ganping Ju

Yingguo Peng

Xi Chen

Xiaobin Zhu

Xiaowei Wu

Dieter Klaus Weller

Jason L Pressesky

Hong Zhou

Jason L Presseky

Determining a Curie temperature (Tc) distribution of a sample comprising magnetic material involves subjecting the sample to an electromagnetic field, heating the sample over a range of temperatures, generating a signal representative of a parameter of the sample that changes as a function of changing sample temperature while the sample is subjected to the electromagnetic field, and determining the Tc distribution of the sample using the generated signal and a multiplicity of predetermined parameters of the sample.

Method and apparatus for determining Curie temperature distribution of a sample of magnetic material

Method and apparatus for determining curie temperature distribution of a sample of magnetic material

A method and apparatus for determining volume and anisotropy field distribution of thin film granular material includes the use of a magneto-optic probe, a lock-in amplifier, and a computer. The magneto-optic probe utilizes the Kerr effect in order to determine the transverse AC susceptibility of the sample. The Lock-in amplifier determines the complex parameters of the susceptibility as a function of the DC field and AC frequency. Separate distribution values of anisotropy field and grain volume can then be determined mathematically from the relationship of complex susceptibility parameters to the DC field strength.

Complex transverse AC magneto-optic susceptometer for determination of volume and anisotropy field distribution in recording media

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Anglesey, United Kingdom

Roy William Chantrell