3,113 research outputs found
Local interactions in magnetic and ferroelectric materials: magnetic and vibronic couplings
No full textBeter rekenen aan magnetische materialen Veel materialen die overgangsmetaalionen bevatten, vertonen fascinerende verschijnselen die kunnen leiden tot belangrijke technologische toepassingen. Dat geldt zeker voor de magnetische eigenschappen van de materialen die Muizz Pradipto in zijn proefschrift bespreekt. De materialen bevatten overgangsmetaal-ionen met gedeeltelijk gevulde d-schillen. De magnetische eigenschappen daarvan worden bepaald door de interactie tussen ongepaarde spins. Isotrope interacties leiden tot parallelle of anti-parallelle uitlijning van de spins. Het gaat dan om respectievelijk ferromagnetische en antiferromagnetische interacties. Als relativistische effecten aanwezig zijn, zoals spin-baan koppeling, zijn echter ook anisotrope interacties tussen de spinmomenten mogelijk. De ontdekking van ferro-elektriciteit in materialen met een spiraal-magnetische ordening voegt een belangrijk aspect toe aan de magnetische anisotropie, in het bijzonder die van de Dzyaloshinskii-Moriya interacties. Maar ondanks het belang van magnetische anisotrope interacties is het onderzoek hieraan tot nu toe zeer beperkt geweest in vergelijking met dat aan magnetische isotrope interacties. Dit komt onder meer door problemen in de afleidingsprocedures voor anisotrope interactie-parameters. In zijn proefschrift bespreekt Abdul Muizz Pradipto methoden om anisotrope interacties te berekenen, als aanvulling op de isotrope. Vervolgens past hij deze methoden toe op de multiferroïsche materialen CuO en LiCu2O2. Daarnaast onderzocht hij twee modellen die ferro-elektrische instabiliteit beschrijven; het soft-mode model en het vibratie interactie model. Hij licht de resultaten toe voor het prototype ferro-elektrische materiaal BaTiO3
Local interactions in magnetic and ferroelectric materials:magnetic and vibronic couplings
No full textBeter rekenen aan magnetische materialen Veel materialen die overgangsmetaalionen bevatten, vertonen fascinerende verschijnselen die kunnen leiden tot belangrijke technologische toepassingen. Dat geldt zeker voor de magnetische eigenschappen van de materialen die Muizz Pradipto in zijn proefschrift bespreekt. De materialen bevatten overgangsmetaal-ionen met gedeeltelijk gevulde d-schillen. De magnetische eigenschappen daarvan worden bepaald door de interactie tussen ongepaarde spins. Isotrope interacties leiden tot parallelle of anti-parallelle uitlijning van de spins. Het gaat dan om respectievelijk ferromagnetische en antiferromagnetische interacties. Als relativistische effecten aanwezig zijn, zoals spin-baan koppeling, zijn echter ook anisotrope interacties tussen de spinmomenten mogelijk. De ontdekking van ferro-elektriciteit in materialen met een spiraal-magnetische ordening voegt een belangrijk aspect toe aan de magnetische anisotropie, in het bijzonder die van de Dzyaloshinskii-Moriya interacties. Maar ondanks het belang van magnetische anisotrope interacties is het onderzoek hieraan tot nu toe zeer beperkt geweest in vergelijking met dat aan magnetische isotrope interacties. Dit komt onder meer door problemen in de afleidingsprocedures voor anisotrope interactie-parameters. In zijn proefschrift bespreekt Abdul Muizz Pradipto methoden om anisotrope interacties te berekenen, als aanvulling op de isotrope. Vervolgens past hij deze methoden toe op de multiferroïsche materialen CuO en LiCu2O2. Daarnaast onderzocht hij twee modellen die ferro-elektrische instabiliteit beschrijven; het soft-mode model en het vibratie interactie model. Hij licht de resultaten toe voor het prototype ferro-elektrische materiaal BaTiO3
Enhanced perpendicular magnetocrystalline anisotropy energy in an artificial magnetic material with bulk spin-momentum coupling
No full textWe systematically investigate the perpendicular magnetocrystalline anisotropy (MCA) in Co-Pt/Pd-based multilayers. Our magnetic measurement data show that the asymmetric Co/Pd/Pt multilayer has a significantly larger perpendicular magnetic anisotropy (PMA) energy compared to the symmetric Co/Pt and Co/Pd multilayer samples. We further support this experiment by first-principles calculations on CoPt2, CoPd2, and CoPtPd, which are composite bulk materials that consist of three atomic layers in a unit cell, Pt/Co/Pt, Pd/Co/Pd, and Pt/Co/Pd, respectively. By estimating the contribution of bulk spin-momentum coupling to the MCA energy, we show that the CoPtPd multilayer with symmetry breaking has a significantly larger PMA energy than the other multilayers that are otherwise similar but lack symmetry breaking. This observation thus provides evidence of the PMA enhancement due to the structural inversion symmetry breaking and highlights the asymmetric CoPtPd as an artificial magnetic material with bulk spin-momentum coupling, which opens a pathway toward the design of materials with strong PMA.11Nsciescopu
Pioneers of Library Movement in Pakistan
No full textThe paper aims to describe in brief the contribution of seven leaders of Pakistan librarianship, viz. K.B. Khalifa M. Asadullah, Prof. Dr. Abdul Moid, Dr. Abdus Subuh Qasimi, Muhammad Shafi, Fazal Elahi, Khawaja Nur Elahi and S. V. Hussain. The early library developments are given for better understanding of the role of these leaders
Book Talk with Author: Puan Faza Fayza Mohd Fawzy
No full textPenerbit UiTM dengan kerjasama Perpustakaan Tun Abdul Razak (PTAR) menjemput seluruh warga kampus dan masyarakat untuk menyertai secara langsung program Book Talk with Author, sebuah inisiatif kolaboratif dalam usaha membudayakan ilmu melalui pembacaan dan perbincangan buku
Slater-Pauling-like Behavior of Spin Hall Conductivity in Pt-based Superlattices
No full textThe intrinsic spin Hall effect in the bulk systems of late transition metals (Os, Ir, Pt, and Au) as well as the Pt-based superlattices were investigated by using first-principle calculations. By comparing the computed spin Hall conductivities of Pt−M superlattices (M=Os, Ir, and Au) with different compositions and those obtained from atomic bulk composition, we saw that the spin Hall conductivities (SHCs) follow the behavior described by the Slater-Pauling curve, the maximum of which is at pure Pt bulk. From the examination of the band structures of the considered systems, we found that the origin of this behavior comes from the variation of the band structures as a direct consequence of the change of the number of electrons and hybridization effects
Magnetic interactions in LiCu2O2: Single-chain versus double-chain models
No full textThe possible origin of the spiral spin structure in multiferroic LiCu2O2 is studied by calculating all relevant isotropic and anisotropic magnetic interactions in the material. The coupling constants are extracted from accurate ab initio quantum chemical calculations with an effective Hamiltonian theory. First, the anisotropic or Dzyaloshinskii-Moriya interactions are found to be negligible. Secondly, we obtain small isotropic interactions of the spin moments located on different chains, which classifies the material as a quasi-one-dimensional magnetic system. The intrachain isotropic interactions between nearest neighbors are relatively large and ferromagnetic, while second-neighbor interactions along the chain have antiferromagnetic character and are about half the magnitude of the former. This frustration leads to a spiral spin structure, which can be subjected to electric polarization.
Shaykh Abdul Qadir Bin Abdul Rahim Bukit Bayas Dan kitabnya risalah fi Bayan Hukm Al-Bay? Wa Al-Riba: satu sorotan
No full textIn the past, Malay Muslims contributed by enriching the collection of writings. Among them is Shaykh ‘Abdul Qadir bin ‘Abdul Rahim Bukit Bayas. His book, entitled Risalah Fi Bayan Hukm Al-Bay’ Wa Al-Riba is an essential reference, particularly in discussingFiqh al- Mu’amalat. This study will attempt to highlight the author’s biodata and the history of the book, how the manuscript is tracked, as well as analysing the content of his book. The data were collected from library research, documentation method and interviews. Then, they were analysed by analysis content method. The study found that Shaykh is one of the Malay scholars who played a role in delivering the Fiqh al-Mu’amalat in the local mould. In conclusion, the author is considered to be an influential scholar in Terengganu although he is not so famous. The book should be consulted in order to gain benefit therefrom
ANALISIS WACANA KRITIS DI MEDIA SOSIAL (STUDI PADA FENOMENA PRO-KONTRA PENOLAKAN DAKWAH USTADZ ABDUL SOMAD)
No full textDa'wah and technological development are inseparable, this is based on the concept of contemporary da'wah that is easily accepted by the present, various new phenomena such as the case of rejection of clerics in several regions arise along with the rise of activity on social media, which incidentally is full of information which is not necessarily true (Tornberg & Tornberg, 2016: 132-134). The news of the pros and cons of rejecting the da'wah experienced by Ustadz Abdul Somad was forwarded freely on social media, one of the social media is twitter. In analyzing discourse on social media, especially Twitter, the author uses analysis technic of critical discourse analysis theory by Norman Fairclough to dismantle discourse practices (Eriyanto, 2015: 285), and includes Antonio Gramsci's theory of hegemony to see discourse battles (Ives, 2004: 63 ) in the phenomenon of Ustadz Abdul Somad's rejection. The results of this study include: (1) The issue of the affiliation of Ustadz Abdul Somad can be mediated with tabayyun and clarification through the media, both traditional and social. However, the issue of khilafah is growing until it displays a process of mutual accusation between the parties involved in the discourse of the khilafah revival; 2) The discourse of Ustadz Abdul Somad's rejection on social media in this study contains trends from two different ideologies namely Nahdlatul Ulama (NU), and Hisbut Tahrir Indonesia (HTI (3) The other tendencies are also influenced by political interests; 4) Between HTI and Banser has an impact on the image of Prabowo's and Jokowi's strongholds with the issue of the fight. HTI was identified as part of opposition supporters, while the impact on the Jokowi camp with anti-Islamic issues, because it was deemed not to show an attitude to clean up the chaos caused by burning the flag at the commemoration of the “Hari Santri Nasional
External electric field driven modification of the anomalous and spin Hall conductivities in Fe thin films on MgO(001)
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