Physics Commons^™

Atomic Disorder Induced Modification Of Magnetization In Mncrval, Juliana Herran, Rishabh Dalal, Paul Gray, Parashu Kharel, Pavel Lukashev

Faculty Publications

We have investigated the physical mechanism behind magnetization reduction in a potential spingapless semiconducting compound MnCrVAl by analyzing various atomic disorder schemes. In particular, we show that depending on the degree of disorder, exchanging atomic positions between Mn/Cr and V/Al leads to reduced total magnetization due to either spin flip, or vanishing spin magnetic moments. The latter is attributed to the itinerant character of magnetism in Cr-, Mn-, and V-containing Heusler alloys, and to the frustration of antiferromagnetic exchange interactions, and is accompanied by a tetragonal distortion, but such distortion alone (i.e., in a fully ordered crystal, with no atomic …

Crosssections, Spring 2017, University Of Northern Iowa. Department Of Physics.

CrossSections

Inside This Issue:
--A Message From the Department Head, Dr. Paul Shand
--Student Profile: Lucas Beving
--Faculty Profile: Tim Kidd
--Department Happenings
--Alumni Feature: Noah Podolefsky
--Science Education
--Olson Retirement Letter
--Listing and Solicitation

Tio2 Coating Method For Nanocellulose Aerogel, Byron Fritch, Tim Kidd

Research in the Capitol

Titanium dioxide has been shown to be an effective catalyst for splitting water into hydrogen and oxygen gas. By increasing the surface area of the titanium dioxide catalyst, the rate of water splitting may increase. A possible method to increase the splitting of water uses a high surface area composite material formed by coating nanocellulose aerogels with titanium dioxide. Different coating methods were studied using titanium isopropoxide as the titanium dioxide source to create such composites. It was found that the most consistent titanium dioxide coatings were formed during a 12 hour titanium isopropoxide vapor bath. Other coating methods collapsed …

Effect Of Structural Disorder On Magnetic Properties Of Mncrval, Juliana Herran, Rishabh Dalal, Paul Gray, Pavel Lukashev

Research in the Capitol

Operation of virtually any modern electronic device relies on magnetic materials. In particular, these materials are the cornerstone of data storage and processing in computer hardware elements, such as hard drives and random access memories. Here, we theoretically study an interplay between structural and magnetic properties of MnCrVAl, a material which recently attracted significant attention due to its rather exotic electronic structure. In particular, this material behaves either as an insulator or as a metal, depending on which “spin” (an intrinsic property of any fundamental particle) of the electron is considered. Using advanced computer simulation techniques (density functional calculations on …

Magnetic Behavior Of Bulk And Nanostructured Mnxtas2, Lucas Paul Beving

Honors Program Theses

At its base, material science research aims to categorize specific materials by their various attributes, such as structure, integrity, electronic properties, magnetic properties, and others. By categorizing materials in this way, it becomes easier to generalize the application of a specific material to those within a broader category. The interest in materials that exhibit useful characteristics at small scales derives directly from the technology industry’s need for smaller and smaller devices. Two-dimensional materials are of great interest for this reason.

Two-dimensional materials are comprised of many single layers, or planes, stacked together to create a crystal. Each layer may be …

Effect Of Fe Substitution On The Structural, Magnetic And Electron-Transport Properties Of Half-Metallic Co2tisi, Y. Yin, J. Waybright, P. Kharel, I. Tutic, J. Herran, P. Lukashev, S. Valloppilly, D. J. Sellmyer

Faculty Publications

The structural, magnetic and electron-transport properties of Co₂Ti_1-xFe_xSi (x = 0, 0.25, 0.5) ribbons prepared by arc-melting and melt-spinning were investigated. The rapidly quenched Co₂Ti_0.5Fe_0.5Si crystallized in the cubic L2₁ structure whereas Co₂Ti_0.75Fe_0.25Si and Co₂TiFe₀Si showed various degrees of B2-type disorder. At room temperature, all the samples are ferromagnetic, and the Curie temperature increased from 360 K for Co₂TiSi to about 800 K for Co₂Ti_0.5Fe_0.5Si. The measured magnetization also …