A magnetic property measuring system includes a stage configured to hold a sample and a magnetic structure disposed over the stage. The stage includes a body part, a magnetic part adjacent the body part, and a plurality of holes defined in the body part. The magnetic part of the stage and the magnetic structure are configured to apply a magnetic field, which is perpendicular to one surface of the sample, to the sample. The stage is configured to move horizontally in an x-direction and a y-direction which are parallel to the one surface of the sample.

A hard disk drive includes a base deck, a cover coupled to the base deck to create an internal cavity, and a testing assembly coupled to the cover. The testing assembly includes a housing and is arranged to expose an organic material, for example grease or oil, to the internal cavity.

A computer-implemented method to detect a damaged tunneling magnetoresistance (TMR) sensor includes applying current at at least two different current values to the TMR sensor and measuring a resistance, R.sub.TMR, at each current value. The method also includes measuring a slope in resistance vs. bias current, RD.sub.SLP, using the measured resistances R.sub.TMR and the at least two different current values. The method includes calculating a RD.sub.SLP value as a difference between the RD.sub.SLP value and an expected value, RD.sub.SLP-expected, for the TMR sensor. The method includes determining whether the RD.sub.SLP value is within a predefined range. In response to determining that the RD.sub.SLP value is outside the predefined range, the method includes outputting an indication that the TMR sensor fails. In response to determining that the RD.sub.SLP value is within the predefined range, the method includes outputting an indication that the TMR sensor passes.

Systems and methods are provided for analyzing magnetic hysteresis of anisotropic magnetic materials. Magnetic hysteresis loops associated with a local coordinate of a coordinated system based on a magnetic field successively applied to each principal axis with an isotropic vector play model are determined. A relaxation factor associated with the convergence behaviors of estimated solution points is applied along with a correction, either a magnetic field correction or a flux density correction, to determine target points on magnetic hysteresis loops. An error between magnetic hysteresis loops and the estimated solution points is determined. The iteration process continues up to a preset number of iterations with alternating correction schemes based on the determined error.

Described are embodiments to calibrate read sensors, which in turn may ensure that the equipment utilized to detect antigens is reliable and accurate. If it is determined that a read sensor is degraded a method of calibrating a read sensor of a read head may be used.

A magnetic property measuring system includes a stage configured to hold a sample and a magnetic structure disposed over the stage. The stage includes a body part, a magnetic part adjacent the body part, and a plurality of holes defined in the body part. The magnetic part of the stage and the magnetic structure are configured to apply a magnetic field, which is perpendicular to one surface of the sample, to the sample. The stage is configured to move horizontally in an x-direction and a y-direction which are parallel to the one surface of the sample.

Aspects of this disclosure relate to one or more particles that move within a container in response to a magnetic field. A measurement circuit is configured to output an indication of the magnetic field based on position of the one or more particles.

A multilayer exchange spring recording media consists of a magnetically hard magnetic storage layer strongly exchange coupled to a softer nucleation host. The strong exchange coupling can be through a coupling layer or direct. The hard magnetic storage layer has a strong perpendicular anisotropy. The nucleation host consists of one or more ferromagnetic coupled layers. For a multilayer nucleation host the anisotropy increases from layer to layer. The anisotropy in the softest layer of the nucleation host can be two times smaller than that of the hard magnetic storage layer. The lateral exchange between the grains is small. The nucleation host decreases the coercive field significantly while keeping the energy barrier of the hard layer almost unchanged. The coercive field of the total structure depends on one over number of layers in the nucleation host. The invention proposes a recording media that overcomes the writeability problem of perpendicular recording media.

A multilayer exchange spring recording media consists of a magnetically hard magnetic storage layer strongly exchange coupled to a softer nucleation host. The strong exchange coupling can be through a coupling layer or direct. The hard magnetic storage layer has a strong perpendicular anisotropy. The nucleation host consists of one or more ferromagnetic coupled layers. For a multilayer nucleation host the anisotropy increases from layer to layer. The anisotropy in the softest layer of the nucleation host can be two times smaller than that of the hard magnetic storage layer. The lateral exchange between the grains is small. The nucleation host decreases the coercive field significantly while keeping the energy barrier of the hard layer almost unchanged. The coercive field of the total structure depends on one over number of layers in the nucleation host. The invention proposes a recording media that overcomes the writeability problem of perpendicular recording media.

Described are probe assemblies that include multiple layers, including at least one layer of probe bodies; suspension assemblies and components thereof, e.g., head gimbal assemblies, that include a probe assembly as described; and methods of using the probe assemblies and suspension assemblies.