Masafumi Kumano

Semiautomatic mutual inductance bridge for magnetic susceptibility measurements

A semiautomatic Hartshorn bridge has been designed to improve the complicated adjusting procedures of the bridge in the measurements of magnetic susceptibilities. The bridge is useful for a continuous recording of the susceptibility of a sample, especially when it varies with time.

Fabrication and characterization of laterally-driven piezoelectric bimorph MEMS actuator with sol?gel-based high-aspect-ratio PZT structure

This paper reports on the fabrication and characterization of a novel laterally-driven piezoelectric bimorph micro electro mechanical systems actuator with high aspect-ratio (AR) lead?zirconate?titanate (PZT) structures. The PZT structures (AR=8) sandwiched with Pt sidewall electrodes were fabricated by a nanocomposite sol?gel process with micromachined silicon templates. A single-cantilever-type lateral bimorph actuator was successfully fabricated, and no initial vertical bending was observed, even on a 500??m long actuator. A lateral displacement of 10??m was obtained in bimorph actuation at driving voltages of?+25?V/?5?V. Then the piezoelectric property of the PZT structure was characterized from the actuators performance. The lateral piezoelectric actuator has a variety of potential applications as a replacement for electrostatic comb drive actuators occupying a large area.

Modified variable temperature control unit for NMR spectrometers

A variable temperature control unit for NMR spectrometers was modified to improve the accuracy of the temperature setting and to suppress the drift and fluctuation of the sample temperature within ±0.1 °C.

Conformal coating of poly-glycidyl methacrylate as lithographic polymer via initiated chemical vapor deposition

This study reports on the investigation of the conformability and photo and electron beam (EB) patternability of a poly-glycidyl methacrylate (PGMA) film formed by initiated chemical vapor deposition (i-CVD). It is demonstrated that the PGMA film can be conformally deposited on a Si trench structure via i-CVD. In addition, the pattern definition of the film is also successfully demonstrated by deep ultraviolet and EB lithography. These achievements indicate that i-CVD has the potential to become a powerful method to achieve the conformal coating of a lithographic resist.

Anisotropic EPR line-width in a linear chain-like organic free radical, TANOL

Abstract Measurement of EPR line widths for a single crystal of TANOL(4-hydroxy-2,2,6,6-tetramethylpiperidinoxy) at room temperature revealed the direction of the linear chain to be the c-axis of the crystal.

Long range ordering of a linear-chain Heisenberg antiferromagnet, tanol, below 1 K

Abstract Magnetization of TANOL (4-hydroxy-2, 2, 6, 6-tetramethylpiperidinoxy) has been measured with the proton NMR method below 1 K. The antiferromagnetic transition temperature T N is determined to be 0.49 ± 0.01 K under an external magnetic field of 1.6 kOe, which is in good agreement with the value obtained by Boucher et al. from a heat capacity measurement. The reason of the discrepancy between this value and the previously reported one is discussed. The sublattice magnetization as a function of temperature, M ( T ), is represented by (1 − 0.729 T 2 ) in the region below 0.35 K. Critical index of the magnetization, β, is estimated to be 0.335 ± 0.02.

Magnetic susceptibility of a linear chain antiferromagnet, TANOL, at very low temperatures

Abstract The magnetic susceptibility of powdered crystals of TANOL (4-hydroxy-2,2,6,6-tetramethylpiperidinol-1-oxy) has been measured in the temperature range between 4.2 and 0.1 K. The results are compared with the theoretical calculations of Bonner and Fisher. Below 0.43 K, an interesting thermal behavior has been observed, which is thought to be associated with a first order phase transition. T N is estimated to be 0.34 K from the thermal behavior of the sample.

Removal of SU-8 by two types of hot-wire atomic hydrogen sources—Dissection of contributions by atomic hydrogen and substrate heating

The removal of the permanent photoresist SU-8 by atomic hydrogen was studied using hot-wire reactors of the conventional open type and the remote type. The remote type hot wire reactor has a separate glass chamber for hydrogen decomposition via the hot wire, and can supply atomic hydrogen to a substrate without significant radiation from the hot wire. Therefore, the atomic hydrogen density and substrate temperature can be independently controlled. Using the remote type setup together with the conventional open type setup, the authors demonstrated that the presence of atomic hydrogen in combination with substrate heating was necessary to completely remove SU-8. At a substrate temperature below 150 °C, the SU-8 removal rate was impractically small. In addition, after the apparent removal of SU-8 a white powder-like residue was found on the sample, which was identified with x-ray photoelectron spectroscopy as silicon components that originated from the silane coupling agent in SU-8. At a substrate temperatur...

Spin flopping transition in a linear chain-like organic free radical, tanol, below 0.5 K

Abstract A spin flopping transition in a linear chain-like organic free radical, TANOL, has been observed below 0.5 K. The maximum value of the anisotropy energy was estimated to be 230 erg/cm 3 . The origin of the magnetic anisotropy is discussed. The temperature dependence of the flopping field is also reported.

Temperature inhomogeneity in the glass mixing chamber of a 3He/4He dilution refrigerator

The temperature inhomogeneity in the glass mixing chamber of a (3)He/(4)He dilution refrigerator has been studied. The inhomogeneity is reduced to 10 mK by inserting a cylindrical spacer in the mixing chamber.