다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

Magnetocaloric effect: From materials research to refrigeration devices

Preface. Contents of volumes 1-6. 1. Magnetism in ultrathin transition metal films (U. Gradmann). 2. Energy band theory of metallic magnetism in the elements (V.L. Moruzzi, P.M. Marcus). 3. Density functional theory of the ground state magnetic properties of rare earths and actinides (M.S.S. Brooks, B. Johansson). 4. Diluted magnetic semiconductors (J. Kossut, W. Dobrowolski). 5. Magnetic properties of binary rare-earth 3d-transition-metal intermetallic compounds (J.J.M. Franse, R.J. Radwanski). 6. Neutron scattering on heavy fermion and valence fluctuation 4f-systems (M. Loewenhaupt, K.H. Fischer). Author index. Subject index. Materials index.

Handbook of Magnetic Materials

H E Stanley Oxford: University Press 1971 pp xx + 308 price ?5 In the past fifteen years or so there has been a lot of experimental and theoretical work on the nature of critical phenomena in the neighbourhood of second order phase transitions. It has not been easy to get a good overall view of this work without digging through the rather complex original literature, although there are some good review articles covering particular aspects of the work.

https://iopscience.iop.org/article/10.1088/0031-9112/23/4/018/pdf

Introduction to Phase Transitions and Critical Phenomena

We report discovery of collinear-magnetism-driven ferroelectricity in the Ising chain magnet Ca3Co2-xMn(x)O6 (x approximately 0.96). Neutron diffraction shows that Co2+ and Mn4+ ions alternating along the chains exhibit an up-up-down-down ( upward arrow upward arrow downward arrow downward arrow) magnetic order. The ferroelectricity results from the inversion symmetry breaking in the upward arrow upward arrow downward arrow downward arrow spin chain with an alternating charge order. Unlike in spiral magnetoelectrics where antisymmetric exchange coupling is active, the symmetry breaking in Ca3(Co,Mn)2O6 occurs through exchange striction associated with symmetric superexchange.

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Ferroelectricity in an Ising Chain Magnet

We report a study of physical properties of rare-earth caged structured compound DyFe2Al10. This compound has been synthesized by Arc melting method and it crystallizes in orthorhombic structure with space group Cmcm. The temperature dependent magnetic susceptibility shows that this compound undergoes paramagnetic to antiferromagnetic transition at TN ∼ 6.9 K. Below TN field induced metamagnetic transitions are clearly visible in field dependent isothermal magnetization. The nature of these transitions has been explored using Arrott plots.

Magnetic studies of caged compound DyFe2Al10

Only 15% to 20% of tenured faculty at Indian universities are women, while 14% of employed researchers in STEM fields are women. To investigate reasons for this problem, the present research study was conducted to gather data for Indian respondents’ perceptions of the reasons for understanding of the women underrepresentation in STEM (Science, Technology, Engineering, Mathematics) fields, focusing on female teenagers. The study asked respondents to rate the overall underrepresentation and the importance of different factors on a scale of 1 to 7, along with their own explanations and suggestions. The study found that the most important factor to explain the underrepresentation was Poverty, followed by Parent’s Traditional values. In contrast, the least important factors were Feminine Attributes and the idea that female teenagers wanted to avoid the male field, while Absorb Stereotypes (the idea that female teenagers subconsciously take in stereotypes of STEM being a male field), Teacher’s Discouragement and Less Confidence were given ratings closer to the middle. Additional factors suggested by respondents included females having to take care of family responsibilities and lack of role models in STEM fields. This suggests Indians have increased awareness of the underrepresentation of women in STEM fields.

Exploring Indian Views on the underrepresentation of female teenagers in STEM

We report the magnetic, thermodynamic, and transport properties of a heavy fermion compound CeNiGe2. This compound undergoes two antiferromagnetic transitions around 4.1 and 3 K. It is observed in heat capacity that as magnetic field is increased to ~ 1 T, the two peak merge into a single peak around 3 K. However this peak is not suppressed under the application of magnetic field. Instead a new feature develops at 3.6 K above 1 T. The magnetic field induced new feature is investigated through entropy evolution, magnetic Gruneisen parameter and resistivity studies. These studies emphasis the fact that partial magnetic frustration due to field induced spin fluctuation is responsible for this observed feature. This partially frustrated regime develops a new antiferromagnetically ordered phase at high fields. In this compound magnetic field induced QCP is absent implying that the behavior of CeNiGe2 is not in accordance to Doniach model proposed for heavy fermions compounds.

Signature of partially frustrated moments and a new magnetic phase in CeNiGe2

Quantum fluctuations and related phase transitions are of current interest from the viewpoint of fundamental physics and technological applications. Quantum phase implies a region where the quantum fluctuations of energy scale $\hbar\omega$ dominates over the thermal energy $k_B$T. Presence of quantum phase leads to unconventional and unexpected physical phenomena like Kondo effect, non-Fermi liquids, ordered magnetic state, and Fermi liquids, etc. In this framework, Ce-based metallic compounds, exhibiting correlated electron phenomena, emerged as prototypical systems to study the various quantum phases. In these systems considerable efforts have been made, both experimentally and theoretically, to overcome the problems related to the comprehensive understanding of correlated quantum phases. In this article, various aspects related to quantum phases in CeNiGe2, CeGe and CeAlGe are summarized, mainly focusing on the structural and physical properties.

Quantum phases in f-Electron Systems.

Half Heusler (HH) alloys with 18 valence electron count have attracted significant interest in the area of research related to thermoelectrics. Understanding the novel transport properties exhibited by these systems with semiconducting ground state is an important focus area in this field. Large thermal conductivity shown by most of the HH alloy possesses a major hurdle in improving the figure of merit (ZT). Additionally, understanding the mechanism of thermal conduction in heavy constituents HH alloys is an interesting aspect. Here, we have investigated the high temperature thermoelectric properties of ZrIrSb through experimental studies, phonon dispersion and electronic band structure calculations. ZrIrSb is found to exhibit substantially lower magnitude of resistivity and Seebeck coefficient near room temperature, owing to existence of anti-site disorder between Ir/Sb and vacant sites. Interestingly, in ZrIrSb, lattice thermal conductivity is governed by coupling between the acoustic and low frequency optical phonon modes, which originates due to heavier Ir/Sb atoms. This coupling leads to an enhancement in the Umklapp processes due to the optical phonon excitations near zone boundary, resulting in a lower magnitude of \k{appa}L. Our studies point to the fact that the simultaneous existence of two heavy mass elements within a simple unit cell can substantially decrease the lattice degrees of freedom.

K. Mukherjee

Papers

Magnetic studies of caged compound DyFe2Al10

Exploring Indian Views on the underrepresentation of female teenagers in STEM

Signature of partially frustrated moments and a new magnetic phase in CeNiGe2

Quantum phases in f-Electron Systems.

Optical phonon modes assisted thermal conductivity in p-type ZrIrSb Half-Heusler alloy: A combined experimental and computational study