Diagram of a flux-coupled dipolar magnet based on a permanent magnet rod with diametric magnetization mounted to a motor. The permanent magnet is indicated by the blue rectangle. The motor is indicated by the brown hashed region, and the steel bars by the black dotted regions. The pole pieces (solid grey with black stripes) are adjustable for changing the gap length. A test device is drawn between the two pole pieces as the green solid rectangle. The red closed curves symbolize the magnetic field lines in the system.
Distortion of the magnetic field lines from a diametrically magnetized cylinder due to the proximity of a steel bar. The red arrows in both (a) and (b) represent the radial magnetization direction. The red dashed curves in (a) represent the magnetic field lines. The angle θ0 in (b) is the angle between magnetization and the steel surface normal. The red and green curves represent the magnetic field lines coming out from and into the magnetic rod.
Transverse magnetic field between the pole pieces as a function of displacement from the midline. The solid dots are measured with a Gaussmeter probe translated along the x axis and the solid line is a finite element calculation of the field from two uniformly magnetized right cylindrical tips (length 0.625 in., diameter 0.5 in.).
Magnetic field between the pole pieces as a function of time as the permanent magnet is rotated continuously at a rate of 400 rpm. The maximum applied field is seen to be a function of the gap spacing.
FFT spectra indicating the various magnet rotation rates.
FLUXCAP apparatus in a testing configuration. The FLUXCAP motor and steel bars are bolted to aluminum tracks. The NIB yoke is encased in aluminum shells for coupling to the motor with a brass set screw and to two plastic ball bearings at the midpoint and the endpoint of the magnet. Adjustable pole pieces emerge from the steel bars where the test sample has been clamped to the aluminum track and a Gaussmeter probe is attached behind the sample. and sample.
GMR signal versus field for 130 hysteresis loops obtained in 20 s.
Averaged magnetic hysteresis loop of a spin-valve device.
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