https://scholar.dgist.ac.kr/handle/20.500.11750/11797 Mon, 10 Aug 2026 11:59:51 GMT 2026-08-10T11:59:51Z https://scholar.dgist.ac.kr/handle/20.500.11750/60590 Title: A comparative synthesis study of α-MnTe across solid-state, Arc-melting, and Te-flux routes Author(s): Kim, Bomin; Jeong, Yunseong; Baek, Wonjung; Kim, Hobyeong; Rhee, Taeseong; Cho, Beopgil; Choi, Woo-Jae; Ha, Jae-Hyun; Park, Jaemun; Hong, Jung-Il; Kwon, Yong Seung; Seo, Jungpil; Park, Keeseong Abstract: Although alpha-MnTe has attracted renewed interest in both thermoelectric and altermagnetic contexts, direct comparisons of practically accessible synthesis routes within a common experimental framework remain limited. Here, we compare conventional solid-state reaction, arc melting and Te self-flux growth methods under a common framework of composition control and thermal history. Within the explored conditions, the phase outcome depends not only on the nominal starting composition but also on route-dependent synthesis environments, including volatilization in sealed ampoules, repeated remelting and rapid quenching in arc melting, and crystal-flux interfacial segregation in Te self-flux growth. In the solid-state route, slow heating with a slightly Mn-rich starting composition was associated with reduced MnTe2 and alpha-MnTe-dominant products. Arc melting yielded alpha-MnTe-dominant products without post-annealing, accompanied by dendritic-like microstructures. Te self-flux growth yielded single crystals, although a minor MnTe2-rich interfacial or surface layer often remained. While the present dataset does not define a rigorous phase boundary or a definitive mechanistic model, it provides a systematic comparative framework for route-dependent phase outcomes and impurity persistence in alpha-MnTe synthesis. Fri, 31 Jul 2026 15:00:00 GMT https://scholar.dgist.ac.kr/handle/20.500.11750/60590 2026-07-31T15:00:00Z https://scholar.dgist.ac.kr/handle/20.500.11750/60515 Title: Crystallographic Stability and No Evidence of Higher-Order Saddle Points in the HfFe6Ge6-type Kagome Metal ScCo6Ge6 Author(s): Park, Jaemun; Rhee, Taeseong; Cho, Beopgil; Jeong, Yunseong; Hong, Seung-Tae; Kim, Heung-Sik; Park, Keeseong Abstract: While kagome RT6X6 (R = Li, Mg, Zr, and rare-earth metals; T = 3d transition metals; X = Ge/Sn) compounds are widely studied, Co-based RCo6X6 phases remain largely limited to structural reports, with few systematic studies of their physical properties. Here we report Sn-flux-grown single-crystalline ScCo6Ge6 and its structural and physical characterization. Single-crystal X-ray diffraction confirms that ScCo6Ge6 adopts the HfFe6Ge6-type structure rather than the vacancy-driven Y0.5Co3Ge3-type variant. Across the RCo6Ge6 series, structural preference correlates with the Shannon ionic radius of R (8-fold coordination), placing ScCo6Ge6 within the stability range of the HfFe6Ge6-type framework. Magnetization exhibits weak temperature dependence consistent with Pauli-like paramagnetism. The resistivity is well described by a Bloch-Gruneisen form with a Debye temperature exceeding 230 K, consistent with phonon-dominated scattering. Electrical transport also shows a conventional linear Hall response and negligible magnetoresistance, indicative of simple metallic behavior. Electronic structure calculations identify a Ge-derived quadratic saddle point similar to 0.35 eV below E F, with no evidence of higher-order saddle points near the Fermi level. These results highlight that crystallographic stability and physical properties in RCo6Ge6 are governed not only by the Co kagome lattice but also sensitively by the Ge sublattice. Tue, 31 Mar 2026 15:00:00 GMT https://scholar.dgist.ac.kr/handle/20.500.11750/60515 2026-03-31T15:00:00Z https://scholar.dgist.ac.kr/handle/20.500.11750/60502 Title: A comparative synthesis study of α-MnTe across solid-state, Arc-melting, and Te-flux routes Author(s): Kim, Bomin; Jeong, Yunseong; Baek, Wonjung; Kim, Hobyeong; Rhee, Taeseong; Cho, Beopgil; Choi, Woo-Jae; Ha, Jae-Hyun; Park, Jaemun; Hong, Jung-Il; Kwon, Yong Seung; Seo, Jungpil; Park, Keeseong Abstract: Although alpha-MnTe has attracted renewed interest in both thermoelectric and altermagnetic contexts, direct comparisons of practically accessible synthesis routes within a common experimental framework remain limited. Here, we compare conventional solid-state reaction, arc melting and Te self-flux growth methods under a common framework of composition control and thermal history. Within the explored conditions, the phase outcome depends not only on the nominal starting composition but also on route-dependent synthesis environments, including volatilization in sealed ampoules, repeated remelting and rapid quenching in arc melting, and crystal-flux interfacial segregation in Te self-flux growth. In the solid-state route, slow heating with a slightly Mn-rich starting composition was associated with reduced MnTe2 and alpha-MnTe-dominant products. Arc melting yielded alpha-MnTe-dominant products without post-annealing, accompanied by dendritic-like microstructures. Te self-flux growth yielded single crystals, although a minor MnTe2-rich interfacial or surface layer often remained. While the present dataset does not define a rigorous phase boundary or a definitive mechanistic model, it provides a systematic comparative framework for route-dependent phase outcomes and impurity persistence in alpha-MnTe synthesis. Fri, 31 Jul 2026 15:00:00 GMT https://scholar.dgist.ac.kr/handle/20.500.11750/60502 2026-07-31T15:00:00Z https://scholar.dgist.ac.kr/handle/20.500.11750/60458 Title: Magnetic glass behaviors of bicontinuous nanocomposite films fabricated by partial oxidation of Pt-Ni-Co Author(s): Ha, Jae-Hyun; Cho, Beopgil; Park, Jaemun; Kim, Tae-Hwan; Park, Keeseong; Han, Dong-Soo; Hong, Jung-Il Abstract: We report the magnetic properties of metal/oxide hybrid nanocomposite thin films derived from an interpenetrating nanoscale morphology formed by reactive co-sputtering of Pt and Co0.7Ni0.3 in a controlled argon and oxygen atmosphere at room temperature. During deposition, selective oxidation of transition-metal elements of Co and Ni, in the presence of less reactive Pt, drives spontaneous phase separation into ferromagnetic (FM) metallic PtNi and antiferromagnetic (AFM) amorphous CoO nanophases. The resulting nanocomposite constitutes a highly entangled three-dimensional network of FM/AFM domains where characteristic dimensions remain in the order of approximately less than 2 nm. The resulting bicontinuous architecture facilitates dense interfacial spin couplings across the entire volume of the film. Unlike conventional exchange-biased magnetic multilayer systems, the nanocomposite exhibits markedly slow spin dynamics near the magnetic transition region, as evidenced by strong frequency dependence of AC susceptibility. This behavior is attributed to the complex magnetic energy landscape caused by the disordered distribution of AFM regions surrounding the FM phase. At lower temperatures below the blocking point, the FM PtNi phase becomes strongly exchange-coupled with the adjacent AFM CoO, leading to a magnetically frozen state. These observations indicate a re-entrant magnetic glass behavior originated from the nanoscale interfacial frustration in the spontaneously formed multiple magnetic nanophases. Thu, 30 Apr 2026 15:00:00 GMT https://scholar.dgist.ac.kr/handle/20.500.11750/60458 2026-04-30T15:00:00Z