金属・セラミック

31 Jan 2017

Detection of Magnetization Reversal in Magnetic Patterned Array using Magnetic Force Microscopy

Magnetization reversal plays a major role in designing the switching mechanisms of magnetic nanostructures in a high density storage device. In this study, magnetization reversal in a magnetic patterned array sample was successfully investigated using an atomic force microscopy (AFM) system via magnetic force microscopy (MFM). The magnetic property and topography data of a sample surface were obtained simultaneously and the data shows that the two signals are well separated by the two-pass scanning method. The MFM images demonstrate that a majority of the circular dot domain structures with 148 nm width on the sample surface experienced a magnetization reversal during the scan with a few domains remaining in their original state.

23 Dec 2013

Single Crystal Yttrium Iron Garnet (YIG)

Magnetic Properties - (Tunable Magnetic Field MFM) Tunable Magnetic Field MFM (TM-MFM) can be used for high resolution magnetic domain studies under the tunable condition of the magnetic field. The observation of magnetic wall domains can be studied at 50 nm resolution.  The images shown above are MFM images of Yttrium iron garnet (YIG) under different magnetic fields. The magnetic domain change had been observed under different magnetic field.  YIG is a ferrimagnetic material with chemical composition Y3Fe2(FeO4)3, or Y3Fe5O12.  In YIG, the iron ions occupy two octahedral and three tetrahedral sites and the iron ions in the two coordination sites exhibit different spins, resulting in magnetic behavior. Interesting magnetic properties can be obtained by substituting specific sites with rare earth elements. A negative refractive-index metamaterial which responds to magnetic fields can be fabricated by using YIG. Publication using Tunable Magnetic Field MFM Journal: IEEE Transaction on Magnetics, 42(10) October 2006. 3249. Title: Effect of Magnetic Field on the Magnetic Domain Authors: J. B. Kim, Y. P. Lee, K. S. Ryu, S. C. Shin, H. Akinaga, and K. W. Kim;  System: Park Systems XE-100 Abstract: We have observed the magnetic domain evolution under an external magnetic field in an epitaxial MnAs film on GaAs(001) by magnetic force microscopy. Owing to the strain involved, the ferromagnetic –MnAs and the paramagnetic –MnAs phases coexist as self-aligned stripes at room temperature. It was found that a complex magnetic domain structure appeared in the ferromagnetic -phase region at the demagnetized state ( = 0Oe). As the magnetic field increased, the magnetic domain structure was gradually changed, and reached a completely saturated state at = 600 Oe. (more) Fig. 2. (a) AFM and (b)–(d) MFM images at room temperature for 250-nm-thick MnAs film on GaAs(001). All the images were taken from the same scan area (5x5 mm) and position. The magnetic field is applied along the easy axis of magnetization as indicated by the white arrow.

23 Dec 2013

Nanoparticles/Nanotubes

Mechanical Properties (F-D Spectroscopy)     FD spectroscopy on the Ag particle show aberrations associated with the indentation of the nanoparticle. FD spectroscopy on the substrate show no effects of indentation.   Relevant Publications using Park AFM and F-D Spectroscopy Qihua Xiong, N. Duarte, S. Tadigadapa, and P. C. Eklund; Force-Deflection Spectroscopy: A New Method to Determine the Young’s Modulus of Nanofilaments;  Nano Lett., 2006, 6 (9), 1904-1909 Equipment: Park Systems XE-100 Abstract: We demonstrate the determination of Young's modulus of nanowires or nanotubes via a new approach, that is, force-deflection spectroscopy (FDS). An atomic force microscope is used to measure force versus deflection (F−D) curves of nanofilaments that bridge a trench patterned in a Si substrate. The FD data are then fit to the Euler−Bernoulli equation to determine Young's modulus. Our approach provides a generic platform from which to study the mechanical and piezoelectric properties of a variety of materials at the nanoscale level. Young's modulus measurements on ZnS (wurtzite) nanowires are presented to demonstrate this technique. We find that the Young's modulus for rectangular cross section ZnS nanobelts is 52 ± 7.0 GPa, about 30% smaller than that reported for the bulk.