Phys.org July 1. 2024 A nickel-cobalt-manganese-indium magnetic shape-memory alloy, can be deformed and then returned to its original shape by driving it through a phase transition. When subjected to a magnetic field, the material undergoes a magnetic and structural phase transition, during which it absorbs and releases heat. An international team of researchers (USA – Oak Ridge National Laboratory, Texas A&M University, NIST, Russia) showed that localized magnon-phonon hybrid modes, which are inherently spread across reciprocal space, act as a bridge between phonons and magnons and result in substantial magnetic field–induced shifts in the phonons and alter phase stability. They […]
Category Archives: Materials science
Controlling electronics with light: the magnetite breakthrough
Nanowerk June 21, 2024 Symmetry breaking across phase transitions often causes changes in selection rules and emergence of optical modes which can be detected via spectroscopic techniques or generated coherently in pump-probe experiments. An international team of researchers (Switzerland, Poland, Czech Republic, Italy) demonstrated that in magnetite (Fe3O4) light excitation coupled to the critical fluctuations of the charge order and coherently generated structural modes of the ordered phase above the critical temperature of the Verwey transition. According to the researchers their methodology represents an effective tool to study the real-time dynamics of critical fluctuations across phase transitions… read more. TECHNICAL […]
A high-temperature superconductor with zero resistance that exhibits strange metal behavior
Phys.org June 25, 2024 In recent experimental signatures of superconductivity close to 80 K in La3Ni2O7 under pressure, a zero-resistance was not observed. Researchers in China showed that the zero-resistance state does exist in single crystals of La3Ni2O7. They found that the system remained metallic under applied pressures, suggesting the absence of a metal–insulator transition proximate to the superconductivity. Analysis of the normal state T-linear resistance revealed a link between this strange-metal behaviour and superconductivity. This was in line with other classes of unconventional superconductors, including the cuprates and Fe-based superconductors. According to the researchers further investigations exploring the interplay of […]
Cheap yet ultrapure titanium metal might enable widespread use in industry
Phys.org June 17, 2024 Widespread use of titanium is significantly hampered by its strong affinity to oxygen, resulting in elevated manufacturing costs during the refining, melting, and casting processes. Researchers in Japan introduced a high-throughput technique, that effectively reduced the oxygen content in molten titanium to a level suitable for structural material applications, to streamline the mass production of titanium by seamlessly integrating the refining, melting, and casting processes. The process leveraged the high affinity of rare-earth metals, such as yttrium (Y), for oxygen. They utilized the formation reaction of their oxyhalides (YOF) to directly remove oxygen from liquid titanium […]
Molecular sponge for the electronics of the future
EurekAlert June 17, 2024 Porous covalent organic frameworks (COFs) enable the realization of functional materials with molecular precision. Past research has typically focused on generating rigid frameworks where structural and optoelectronic properties are static. Constructing dynamic, yet crystalline and robust frameworks require a well-controlled degree of flexibility. An international team of researchers (UK, Germany, USA – Stony Brook University) has developed dynamic 2D COFs that can open and close their pores upon uptake or removal of guests while retaining their crystalline long-range order. The process requires a well-controlled degree of flexibility. They achieved this through a ‘wine rack’ design where […]
Scientists develop fatigue-free ferroelectric material
Phys.org June 6, 2024 Ferroelectric materials have switchable electrical polarization that is useful for high density non-volatile memories. However, fatigue hinders practical applications of these materials. An international team of researchers (Canada, China) reported a fatigue-free ferroelectric system based on the sliding ferroelectricity of bilayer 3R-MoS2. The memory performance of the ferroelectric device did not show the “wake-up effect” at low cycles or a substantial “fatigue effect” after 106 switching cycles under different pulse widths. The total stress time of device under an electric field was up to 105 s. According to the researchers their theoretical calculation shows that the […]
Study reveals potential of superparaelectric materials as gate dielectrics in next-gen microelectronics
Phys.org May 30, 2024 Previous investigations for thickness-scalable high dielectric constant (k) gate layers have failed to solve the “polarizability–scalability–insulation robustness issues. An international team of researchers (UK, China) showed that this problem could be solved by using a gate layer of a high k ferroelectric oxide in its superparaelectric (SPE) state. They showed that in the SPE, the polar order became local and was dispersed in an amorphous matrix with a crystalline size down to a few nanometers, leading to an excellent dimensional scalability and a good field-stability of the k value. As an example, a stable high k […]
Towards next-gen functional materials: direct observation of electron transfer in solids
Science Daily June 4, 2024 Nanoscale electron transfer (ET) in solids is fundamental to the design of multifunctional nanomaterials, yet its process is not fully understood. Researchers in Japan directly observed solid-state ET via a crystal-to-crystal process. They first demonstrated the creation of a robust and flexible electron acceptor/acceptor (A/A) double-wall nanotube crystal with a large window through the one-dimensional porous crystallization of heteroleptic Zn4 metallocycles with two different acceptor ligands. They constructed the electron donor incorporated-A/A nanotube crystal through the subsequent absorption of electron donor guests. They removed electrons from the electron donor guests inside the nanotube crystal through […]
Researchers create materials with unique combination of stiffness, thermal insulation
Phys.org May 29, 2024 Thermal conductivity and elastic modulus are usually positively correlated in soft materials. A team of researchers in the US (North Carolina State University, Texas A&M University) have shown anomalous correlations of thermal conductivity and elastic modulus in 2D hybrid organic–inorganic perovskites (HOIP) by engineering the molecular interactions between organic cations. By replacing conventional alkyl–alkyl and aryl–aryl type organic interactions with mixed alkyl–aryl interactions, they observed an enhancement in elastic modulus with a reduction in thermal conductivity. The anomalous dependence provided a route to engineer thermal conductivity and elastic modulus independently and a guideline to search for […]
Accelerated discovery research unveils 21 novel materials for advanced organic solid-state laser technology
Phys.org May 16, 2024 To overcome the synthesis bottleneck in molecular discovery, an international team of researchers (Canada, USA – University of Illinois at Urbana-Champaign, industry, UK, Japan, Poland) developed a generalizable two-step one-pot protocol for assembling pentameric organic solid-state laser (OSL) gain materials from modular precursors, spanning over 150,000 target materials. The preparation of building blocks was distributed over the available experimental resources at four geographic locations. They found a total of 21 small-molecule emitters with improved emission gain cross sections compared with state-of-the-art OSL gain materials. The resulting data was fed into the central, machine learning–based experiment planning […]