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Japanese About UsMissionWaseda Vision 150President’s MessageOrganizationHistoryWaseda at a glanceSocial MediaContact UsWASEDA DigestAdmissionsAdmissionsAcademic ListingsJapanese Language CoursesExchange &＃038; Study Abroad ProgramsOnline Courses on edXCampus ToursContact UsResearchResearch Press ReleaseResearch ActivitiesResearcher DatabaseTop Global University ProjectTeaching Resource (Elsevier)Campus LifeStudent Contributor ArticlesEquality, Diversity &＃038; InclusionHealth, Safety &＃038; WellnessIntercultural ExchangeSportsResidential LifeVolunteeringLibraries &＃038; MuseumsStudent CirclesScholarships and Student SupportCollaborationTop Global University Project: Waseda Goes GlobalWasedaXLatest research and commentary on Covid-1910 Years Since the Tohoku Earthquake and TsunamiAlumniGiving StudentsAlumniParents &＃038; GuardiansFaculty &＃038; StaffMedia Academic ListingsContact UsCampus AccessEmergency Notice Accessibility &＃038; CopyrightSitemapPrivacy PolicyMyWasedaSocial MediaEmploymentAnnual Plans・ReportsEquality, Diversity &＃038; Inclusion Syllabus Search Researcher Database Waseda University Repository Seeds Database Waseda E-Resource Portal Cultural Resource Database Announcements Mar 28, 2024 Schedule for Spring 2024 entrance ceremonies Mar 21, 2024 Schedule for Spring 2024 graduation ceremonies Dec 12, 2023 Spring 2024 graduation and entrance ceremonies Sep 19, 2023 Schedule for Autumn 2023 Entrance Ceremonies Sep 7, 2023 Schedule for Autumn 2023 Graduation Ceremonies Waseda University 1-104 Totsukamachi, Shinjuku-ku, Tokyo, 169-8050, JAPAN About UsMissionWaseda Vision 150President’s MessageOrganizationHistoryWaseda at a glanceSocial MediaContact UsWASEDA DigestAdmissionsAdmissionsAcademic ListingsJapanese Language CoursesExchange &＃038; Study Abroad ProgramsOnline Courses on edXCampus ToursContact UsResearchResearch Press ReleaseResearch ActivitiesResearcher DatabaseTop Global University ProjectTeaching Resource (Elsevier)Campus LifeStudent Contributor ArticlesEquality, Diversity &＃038; InclusionHealth, Safety &＃038; WellnessIntercultural ExchangeSportsResidential LifeVolunteeringLibraries &＃038; MuseumsStudent CirclesScholarships and Student SupportCollaborationTop Global University Project: Waseda Goes GlobalWasedaXLatest research and commentary on Covid-1910 Years Since the Tohoku Earthquake and TsunamiAlumniGive Emergencynotice About UsMissionWaseda Vision 150President’s MessageOrganizationHistoryWaseda at a glanceSocial MediaContact UsWASEDA DigestAdmissionsAdmissionsAcademic ListingsJapanese Language CoursesExchange &＃038; Study Abroad ProgramsOnline Courses on edXCampus ToursContact UsResearchResearch Press ReleaseResearch ActivitiesResearcher DatabaseTop Global University ProjectTeaching Resource (Elsevier)Campus LifeStudent Contributor ArticlesEquality, Diversity &＃038; InclusionHealth, Safety &＃038; WellnessIntercultural ExchangeSportsResidential LifeVolunteeringLibraries &＃038; MuseumsStudent CirclesScholarships and Student SupportCollaborationTop Global University Project: Waseda Goes GlobalWasedaXLatest research and commentary on Covid-1910 Years Since the Tohoku Earthquake and TsunamiAlumniGive Emergencynotice Home News Share Mechanism behind magnetism-driven negative thermal expansion (NTE) explained for the first time in over 40 years Tue, Mar 26, 2019 Tags Press Release Research Share A step closer to developing more durable and less heat-sensitive machine parts If you have tried dismantling your own computer, cell phone or any other devices, you will find that the inside of such machines are made up of many small parts and components that are prone to poor performance and damage caused by overheating. As such, there is constantly a market demand to develop machine parts that could resist damage and changes (e.g. changes in size and length) due to heat. Back in junior high or high school, many of us would have learned in science classes that materials expand upon heating and contract upon cooling. In reality, some materials behave the other way around, i.e. expanding upon cooling and vice-versa, an unusual phenomenon known as negative thermal expansion (NTE). NTE materials have thus come under the spotlight worldwide because by utilizing their characteristics and using them in combination with non-NTE materials, developers could make materials that are even less heat-sensitive than before. Unfortunately, the mechanism behind NTE had remained unknown to scientists and developers over the past 40 years. However, for the first time, a recent study led by Professor Masahito Mochizuki at Waseda University and graduate student Masaya Kobayashi from Aoyama Gakuin University was able to provide a theoretical explanation to the NTE phenomenon by examining NTE observed in inverse perovskite antiferromagnets Mn3AN (A = Zn, Ga, etc.). The theory could not only help scientists and developers understand the mechanism behind NTE, but also allow them to predict and identify possible candidate materials that would exhibit NTE—a crucial process in research and development. An electron has an angular momentum called “spin” originating from its rotation. During cooling, the spin vectors of electrons that orbit around the manganese (Mn) ion present in Mn3AN would align themselves in a specific fashion called “non-planar antiferromagnetic order”. It has been known that as temperature decreases, the Mn3AN material would expand in volume. Believing that there is a close relationship between the electron spin alignment and negative thermal expansion phenomena in Mn3AN, Professor Mochizuki and his team decided to investigate the correlations between the two to understand the NTE mechanism by numerically reproducing the crystal-volume expansion upon cooling triggered by the non-planar antiferromagnetic order. “In our study of inverse perovskite antiferromagnets Mn3AN, we have revealed that the mechanism is not specific to the inverse perovskites but might be expected in other crystal structures. Specifically, antiferromagnets in which antiferromagnetic contribution from direct exchange paths and ferromagnetic contribution from indirect 90 degree paths compete severely with each other are potential candidates that could exhibit NTE,” says Professor Mochizuki. Professor Mochizuki and his team believe that the above prediction will be a useful guide to search for new NTE materials because there is no reliable way to seek or identify magnetism-driven NTE materials at present. “Although the existence of such competition is not a sufficient condition but a necessary condition for emergence of the magnetism-driven NTE, search for compounds that satisfy this condition is a strong strategy to discover new NTE materials with profound effects.” adds Professor Mochizuki. Information on the published article Published in Physical Review Materials on February 21, 2019 Title: Theory of magnetism-driven negative thermal expansion in inverse perovskite antiferromagnets Authors: Mochizuki Masahito & Masaya Kobayashi DOI: https://doi.org/10.1103/PhysRevMaterials.3.024407 Related Articles Arts : Asia : Contributor : Culture : Guest : History : Silent Film Reinvented: The Art of the Benshi 2024 World Tour May 16, 2024 SILS 20th Anniversary Celebrations International Symposium: Understanding Human Rights of Stateless People in the Real-life Context in the Asia-Pacific May 15, 2024 Press Release : Research : Sports : Longer Sprint Intervals Can Improve Muscle Oxygen Utilization Compared to Shorter Intervals May 15, 2024 Virtual Campus Tour Waseda Campus Toyama Campus Nishiwaseda Campus Tokorozawa Campus Social Media Instagram facebook X youtube LinkedIn Giving Your generosity can make a difference and bring rippling impact No matter the size, every single gift will make a difference in helping students afford an academic experience that will transform their lives, as well as promoting frontline research to resolve complex challenges of the world today. More About Giving Japanese About UsMissionWaseda Vision 150President’s MessageOrganizationHistoryWaseda at a glanceSocial MediaContact UsWASEDA DigestAdmissionsAdmissionsAcademic ListingsJapanese Language CoursesExchange &＃038; Study Abroad ProgramsOnline Courses on edXCampus ToursContact UsResearchResearch Press ReleaseResearch ActivitiesResearcher DatabaseTop Global University ProjectTeaching Resource (Elsevier)Campus LifeStudent Contributor ArticlesEquality, Diversity &＃038; InclusionHealth, Safety &＃038; WellnessIntercultural ExchangeSportsResidential LifeVolunteeringLibraries &＃038; MuseumsStudent CirclesScholarships and Student SupportCollaborationTop Global University Project: Waseda Goes GlobalWasedaXLatest research and commentary on Covid-1910 Years Since the Tohoku Earthquake and TsunamiAlumniGiving StudentsAlumniParents &＃038; GuardiansFaculty &＃038; StaffMedia Academic ListingsContact UsCampus AccessEmergency Notice Accessibility &＃038; CopyrightSitemapPrivacy PolicyMyWasedaSocial MediaEmploymentAnnual Plans・ReportsEquality, Diversity &＃038; Inclusion Syllabus Search Researcher Database Waseda University Repository Seeds Database Waseda E-Resource Portal Cultural Resource Database Announcements Mar 28, 2024 Schedule for Spring 2024 entrance ceremonies Mar 21, 2024 Schedule for Spring 2024 graduation ceremonies Dec 12, 2023 Spring 2024 graduation and entrance ceremonies Sep 19, 2023 Schedule for Autumn 2023 Entrance Ceremonies Sep 7, 2023 Schedule for Autumn 2023 Graduation Ceremonies Waseda University 1-104 Totsukamachi, Shinjuku-ku, Tokyo, 169-8050, JAPAN