Thermal Stability Of FeTaN As A Function Of N And Ta Content
FeTaN thin films promise to be a good candidate for inductive head pole materials. FeTaN thin films which are nanocrystalline and possess the required magnetic properties in the as-deposited state are advantageous because they do not require a high temperature processing anneal. However, FeTaN films must possess sufficient thermal stability in order to maintain their magnetic properties while being processed into inductive heads. In this study we have undertaken systematic microstructural and magnetic measurements on nanocrystalline, single-layer FeTaN thin films as a function of N and Ta content and annealing temperature. The annealing temperatures used are less than 300/spl deg/C and are meant to simulate head processing conditions. The addition of Ta was found to enhance thermal stability. By stabilizing the microstructure, Ta also stabilizes magnetic properties such as coercivity and magnetostriction (structure determines properties). The optimum amount of Ta for thermal stability while maintaining good magnetic properties was 10 weight percent. In the highest N content Fe-10TaN thin films, soft magnetic properties were found to be controlled by the magnetic domain structures which are governed by magnetoelastic anisotropy. These films which exhibited a magnetoelastic anisotropy less than -2/spl times/10/sup 4/ ergs/cm/sup 3/ also exhibited stripe domains which resulted in relatively high coercivities.
Magnetic and thermal properties of IrMn/FeTaN films
The antiferromagnetic–ferromagnetic exchange coupling between IrMn and FeTaN films has been investigated to study the effects of the exchange field on the high frequency response and the thermal stability of the anisotropy field of FeTaN. Ferromagnetic resonance, vibrating sample magnetometer, and torque measurements were used to determine the values of the unidirectional exchange bias field Hp, the uniaxial anisotropy field Hk and the interfacial energy J. Permeameter measurements to 3 GHz were used to study the effect of the exchange field on the low-frequency permeability and the high-frequency cutoff. Measurements on varying thicknesses of IrMn and FeTaN films gave Hp values from 4 to 115 Oe, Hk values from 10 to 20 Oe, Hc values from 10 to 20 Oe, and an interfacial energy J=0.075 ergs/cm2. The exchange coupling was found to have significant effects on the permeability and the thermal stability of the anisotropy.
Traceability strategy for gear-pitch-measuring instruments: development and calibration of a multiball artifact
There is a strong demand to ensure the traceability of gear-measuring instruments (GMIs). We propose a multiball artifact (MBA) for the evaluation of pitch-measuring accuracy. The aim of the MBA is to transfer the minimum uncertainty from a calibrated value at the National Metrology Institute of Japan (NMIJ) to a measured value of GMIs at a shop floor. The MBA is composed of equally spaced high-accuracy balls around an axis. The pitch-measuring accuracy of GMIs is evaluated by measuring the angular pitch deviation of the balls instead of the angular pitch deviation of a gear. We calibrated the angular pitch deviation using a coordinate measuring instrument (CMM) at the NMIJ and adapting a multiple-orientation technique. We proposed a calibration strategy of the angular pitch deviation. The calibration value of the pitch deviation for the MBA at the NMIJ was obtained with a measurement uncertainty (U95) of 0.2 µm. We evaluated the pitch-measuring accuracy of a GMI using the calibrated MBA. Each value of U95 for the cumulative and single pitch deviations for the left and right flanks was less than or equal to 0.5 µm. The small uncertainty was transferred from the NMIJ to the GMI.