Large Coercivity in Nanostructured Rare-earth-free MnxGa Films

The magnetic hysteresis of MnxGa films exhibit remarkably large coercive fields as high as 2.5 T when fabricated with nanoscale particles of a suitable size and orientation. This coercivity is an order of magnitude larger than in well-ordered epitaxial film counterparts and bulk materials. The enhanced coercivity is attributed to the combination of large magnetocrystalline anisotropy and ~ 50 nm size nanoparticles. The large coercivity is also replicated in the electrical properties through the anomalous Hall effect. The magnitude of the coercivity approaches that found in rare-earth magnets, making them attractive for rare-earth-free magnet applications

Universal Properties of Linear Magnetoresistance in Strongly Disordered Semiconductors

Linear magnetoresistance occurs in semiconductors as a consequence of strong electrical disorder and is characterized by nonsaturating magnetoresistance that is proportional to the applied magnetic field. By investigating a disordered MnAs-GaAs composite material, it is found that the magnitude of the linear magnetoresistance (LMR) is numerically equal to the carrier mobility over a wide range and is independent of carrier density. This behavior is complementary to the Hall effect that is independent of the mobility and dependent on the carrier density. Moreover, the LMR appears to be insensitive to the details of the disorder and points to a universal explanation of classical LMR that can be applied to other material systems.Comment: Accepted by Phys. Rev. B (2010

Nurse-reported vs. Patient-reported Symptom Occurrence, Severity, And Agreement Using The Therapy-related Symptoms Checklist (TRSC) In Cancer Patients

PURPOSE: Developments in cancer treatments have resulted in increased survival of patients, but side effects/symptoms continue to be a concern. The Therapy-Related Symptoms Checklist (TRSC) has been used with adults undergoing cancer treatments. Study purposes were to examine among patients who completed the TRSC: (a) patient-reported symptom occurrence and severity; (b) nurse-reported symptom occurrence and severity; and (c) inter-rater agreement between patient-reported and nurse-reported symptoms. No study on this last question has been reported. Theoretical Framework: Orem’s Self-Care Deficit Theory focuses on individuals unable to meet their own self-care requirements. The TRSC is a tool that assists nurses in identifying these deficits, better facilitates supportive interventions to alleviate the symptoms, and promotes the patient’s/caregiver’s ability to enhance self-care. DESIGN: This is a cross-sectional study using primary data collection and analysis. Setting: The study was conducted on patients at a single outpatient cancer center in a rural community of the Midwestern United States. Participants: A convenience sample (N=22) of adult outpatients undergoing cancer therapy. METHODS: All patients and their nurse completed the TRSC, a 25-item checklist, with response choices ranging from “0” (none) to “4” (very severe). Descriptive statistics were used to address Purposes A and B, and a Pearson product-moment correlation analysis for Purpose C. RESULTS: All symptoms on the TRSC were reported in varying degrees. Regarding Purpose A, 40% or more of the patients reported 14 symptoms. Regarding Purpose B, 40% or more of nurse respondents reported 8 symptoms. In addition to higher symptom occurrence, greater symptom severity also was reported by patients compared to nurses. Regarding Purpose C, the percentage agreement between patient-reported and nurse identified symptoms was 77%, and the Pearson product-moment correlation coefficient was r =.77, indicating moderate agreement. CONCLUSIONS: Use of patient self-report of symptoms is a preferred approach. A standardized tool (the TRSC) can guide nurses in providing a more complete, symptom-focused care. This may then enhance treatment compliance and improved outcomes

Antiferromagnetic phase of the gapless semiconductor V3Al

Discovering new antiferromagnetic compounds is at the forefront of developing future spintronic devices without fringing magnetic fields. The antiferromagnetic gapless semiconducting D03 phase of V3Al was successfully synthesized via arc-melting and annealing. The antiferromagnetic properties were established through synchrotron measurements of the atom-specific magnetic moments, where the magnetic dichroism reveals large and oppositely-oriented moments on individual V atoms. Density functional theory calculations confirmed the stability of a type G antiferromagnetism involving only two-third of the V atoms, while the remaining V atoms are nonmagnetic. Magnetization, x-ray diffraction and transport measurements also support the antiferromagnetism. This archetypal gapless semiconductor may be considered as a cornerstone for future spintronic devices containing antiferromagnetic elements.Comment: Accepted to Physics Review B on 02/23/1

Magnetic properties of Fe/Dy multilayers: a Monte Carlo investigation

We investigate the magnetic properties of a Heisenberg ferrimagnetic multilayer by using Monte Carlo simulations. The aim of this work is to study the local structural anisotropy model which is a possible origin of the perpendicular magnetic anisotropy in transition metal/rare earth amorphous multilayers. We have considered a face centered cubic lattice where each site is occupied by a classical Heisenberg spin. We have introduced in our model of amorphous multilayers a small fraction of crystallized Fe-Dy nanoclusters with a mean anisotropy axis along the deposition direction. We show that a competition in the energy terms takes place between the mean uniaxial anisotropy of the Dy atoms in the nanoclusters and the random anisotropy of the Dy atoms in the matrix.Comment: accepte pour publication - Proceeding of the Joint European Magnetic Symposia (JEMS 06) - Journal of Magnetism and Magnetic Material

Hall carrier density and magnetoresistance measurements in thin film vanadium dioxide across the metal-insulator transition

Temperature dependent magneto-transport measurements in magnetic fields of up to 12 Tesla were performed on thin film vanadium dioxide (VO2) across the metal-insulator transition (MIT). The Hall carrier density increases by 4 orders of magnitude at the MIT and accounts almost entirely for the resistance change. The Hall mobility varies little across the MIT and remains low, ~0.1cm2/V sec. Electrons are found to be the major carriers on both sides of the MIT. Small positive magnetoresistance in the semiconducting phase is measured

Automotive Bankruptcy Panel Discussion - November 16, 2009

This panel discussion concerning bankruptcy and the automobile industry took place in the Joseph W. Bartunek III Moot Court Room on the campus of the Cleveland-Marshall College of Law on November 16, 2009

Monte Carlo investigation of the magnetic anisotropy in Fe/Dy multilayers

By Monte Carlo simulations in the canonical ensemble, we have studied the magnetic anisotropy in Fe/Dy amorphous multilayers. This work has been motivated by experimental results which show a clear correlation between the magnetic perpendicular anisotropy and the substrate temperature during elaboration of the samples. Our aim is to relate macroscopic magnetic properties of the multilayers to their structure, more precisely their concentration profile. Our model is based on concentration dependent exchange interactions and spin values, on random magnetic anisotropy and on the existence of locally ordered clusters that leads to a perpendicular magnetisation. Our results evidence that a compensation point occurs in the case of an abrupt concentration profile. Moreover, an increase of the noncollinearity of the atomic moments has been evidenced when the Dy anisotropy constant value grows. We have also shown the existence of inhomogeneous magnetisation profiles along the samples which are related to the concentration profiles