modern crystalline materials by neutron diffraction method Ludmila - PowerPoint PPT Presentation

Precision investigation of modern crystalline materials by neutron diffraction method Ludmila Šámalová & Alexandru Cr ǎ ciun under supervision of Ivan Bobrikov

matterials

neutron diffraction method • neutrons as waves λ =h/mv • interference • neutron diffraction vs. X-ray • nucleons vs. electrons • different izotops: • different cross section • different energy loose

pulse reactor neutron source

HRFD 1 – Moderator 2 – Fourier Chopper 3 – Guide Tube 4 – Main Detector 5 – Sample Position 6 – 90 -Detector 7 – PSD Detector 8 – VME Control and Operative Visualization/Analysis 9 – VME Station (OS/9) Data Acquisition 10 – EtherNet Data Transfer

Time of Flight • velocity: • energy: • resolution of time of flight diffractometer: • neutron beam intensity

diffraction pattern • peak position – type of atom • peak intensity – location

conditions and tasks • experience with neutron diffraction experiments • technics and principles • refinement real diffraction patterns • instrumental standart samples – Al 2 O 3 , LaB 6 • modern functional material – LiNi 0,5 Mn 1,5 O 4

Standard samples • Al 2 O 3 , LaB 6 • FullProf

LiNi 0.5 Mn 1.5 O 4 the investigated material • Cathode in Li-Ion batteries • Space group Fd3m • Mg doping • LiMg 0.05 Ni 0.45 Mn 1.5 O 4 • a=8.1803 Å • Ni:Mg = 0.342:0.079

impurity • NiO • Space group R3m • a = 2.941349 Å • b = 2.941349 Å • c = 7.174259 Å

Summary • experience with neutron diffraction experiments • technics and principles • refinement real diffraction patterns • instrumental standart samples – Al 2 O 3 , LaB 6 • modern functional material – LiNi 0,5 Mn 1,5 O 4

references • http://chemistry.about.com/od/metalsalloys/ig/Metal-Crystals-Photo- Gallery/Niobium-Crystals.-drr.htm • http://flnp.jinr.ru/136/ • http://flnp.jinr.ru/393/ • Liu Guoqiang (2012). LiNi0.5Mn1.5O4 Spinel and Its Derivatives as Cathodes for Li-Ion Batteries, Lithium Ion Batteries - New Developments, Dr. Ilias Belharouak (Ed.), ISBN: 978-953-51-0077-5, InTech, Available from: http://www.intechopen.com/books/lithium-ion-batteries-new- developments/spinel-lini0-5mn1-5o4-and-itsderivatives-as-cathodes-for- li-ion-batteries • http://www.dragon.lv/exafs/akuzmin/papers/ak147.pdf