High sensitivity and multifunctional micro-Hall sensors fabricated using InAlSb/InAsSb/InAlSb heterostructures

Further diversification of Hall sensor technology requires development of materials with high electron mobility and an ultrathin conducting layer very close to the material's surface. Here, we describe the magnetoresistive properties of micro-Hall devices fabricated using InAlSb/InAsSb/InAlSb heterostructures where electrical conduction was confined to a 30 nm-InAsSb two-dimensional electron gas layer. The 300 K electron mobility and sheet carrier concentration were 36 500 cm(2) V-1 s(-1) and 2.5 x 10(11) cm(-2), respectively. The maximum current-related sensitivity was 2 750 V A(-1) T-1, which was about an order of magnitude greater than AlGaAs/InGaAs pseudomorphic heterostructures devices. Photolithography was used to fabricate 1 mu m x 1 mu m Hall probes, which were installed into a scanning Hall probe microscope and used to image the surface of a hard disk

Strongly Blueshifted Phenomena Observed with {\it Hinode}/EIS in the 2006 December 13 Solar Flare

We present a detailed examination of strongly blueshifted emission lines observed with the EUV Imaging Spectrometer on board the {\it Hinode} satellite. We found two kinds of blueshifted phenomenon associated with the X3.4 flare that occurred on 2006 December 13. One was related to a plasmoid ejection seen in soft X-rays. It was very bright in all the lines used for the observations. The other was associated with the faint arc-shaped ejection seen in soft X-rays. The soft X-ray ejection is thought to be an MHD fast-mode shock wave. This is therefore the first spectroscopic observation of an MHD fast-mode shock wave associated with a flare.Comment: 18 pages, 1 table, 6 figures. ApJ, accepte

First-principles study on the origin of large thermopower in hole-doped LaRhO3 and CuRhO2

Based on first-principles calculations, we study the origin of the large thermopower in Ni-doped LaRhO3 and Mg-doped CuRhO2. We calculate the band structure and construct the maximally localized Wannier functions from which a tight binding Hamiltonian is obtained. The Seebeck coefficient is calculated within the Boltzmann's equation approach using this effective Hamiltonian. For LaRhO3, we find that the Seebeck coefficient remains nearly constant within a large hole concentration range, which is consistent with the experimental observation. For CuRhO2, the overall temperature dependence of the calculated Seebeck coefficient is in excellent agreement with the experiment. The origin of the large thermopower is discussed.Comment: 7 pages, to be published J. Phys.: Cond. Matt., Proc. QSD 200

Status Report of LNS Accelerator Complex in 2002(IV. Status Report of LNS Accelerator Complex in 2002)

Operation status of an electron accelerator complex at Laboratory of Nuclear Science, Tohoku University is reported. After a completion of a new building containing an experimental vault, the inspection for the radiation safety was done in the beginning of October, 2003, so that most of user machine time was consumed in the latter half of the fiscal year 2002

Status Report of LNS Accelerator Complex in 2001(IV. Status Report of LNS Accelerator Complex in 2001)

The electron accelerator complex at the Laboratory of Nuclear Science, Tohoku University has been operated for various fields of science. A 35-year-old 300 MeV electron linac is still working well. However troubles due to aging is rapidly getting serious. In addition, because of multi-purpose use of the linac many different beam characteristics are requested by the users, so that the operation mode has been complicate. In this report, the operation status of the accelerator complex including major troubles experienced in the fiscal year 2001 is described and future plan is shortly discussed by showing the present machine operation

Transport properties of the layered Rh oxide K_0.49RhO_2

We report measurements and analyses of resistivity, thermopower and Hall coefficient of single-crystalline samples of the layered Rh oxide K_0.49RhO_2. The resistivity is proportional to the square of temperature up to 300 K, and the thermopower is proportional to temperature up to 140 K. The Hall coefficient increases linearly with temperature above 100 K, which is ascribed to the triangular network of Rh in this compound. The different transport properties between Na_xCoO_2 and K_0.49RhO_2 are discussed on the basis of the different band width between Co and Rh evaluated from the magnetotransport.Comment: 3 figures, submitted to PR