prof. dr. E.W. Gorter his contributions to structural chemistry in - - PowerPoint PPT Presentation

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prof. dr. E.W. Gorter his contributions to structural chemistry in - - PowerPoint PPT Presentation

Dec 21, 2022 177 likes •428 views

prof. dr. E.W. Gorter his contributions to structural chemistry in relation to physical properties Jacob van Dijk (CHG) Kees Plug (CHG) 1 Compliments by W.G.Burgers (1961) 2 Evert Willem Gorter 1912 (Leiden) -1972 (Leiden) 3 Gorter (left)

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  • prof. dr. E.W. Gorter

his contributions to structural chemistry in relation to physical properties

Jacob van Dijk (CHG) Kees Plug (CHG)

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Compliments by W.G.Burgers (1961)

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Evert Willem Gorter

1912 (Leiden) -1972 (Leiden)

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Gorter (left) with J. van Ormondt

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Ferrites

  • Early history

– Verwey was first to exploit this research line 1935 – Van Arkel published article with Verwey as early as 1936 – Snoek did write first booklet about ferrites 1947

  • Why did ferrites receive so much attention?

– availability cheap raw materials – electrical isolator – flexibility of composition & magnetic properties – novelty

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Spinel Mg Al2O4

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Dilution of M(II)Fe2O4 with Zn

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Predicted Néel anomaly

Li0,5Fe2,5-aCra04

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Néel theory

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Super-exchange “model Gorter”

Spin ordering BaFe12O19

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Letter E.W.Gorter

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Gorter: Thesis and Inaugural Address

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Gorter’s approach

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Chemical Composition Crystal Structure Physical Properties

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Gorter with his “blokje”

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Gorter blokje

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Close packed layers A B C

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A B C

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CCP = Cubic Close Packed FCC = Face Centered Cubic

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A B C A

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Gorter blokje of NaCl + NiAs

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Gorter blokje of CdCl2 + Cd(OH)2

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Gorter blokje of TiO2 Rutile + Anatase

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Gorter blokje of spinel

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Gorter’s representation of CaFe2O4

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Face shared octahedra Ca-ion in 9-coordination

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Hyde’s representation of CaTi2O4

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Face shared octahedra

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Conclusions

– Gorter was eminent scientist/group leader at Philips directly after the war

  • Ferroxcube / Ferroxdure
  • Confirmation Neel theory
  • Model for super exchange in hexagonal ferrites

– Gorter’s time as professor at Leiden

  • Too short to form a real school
  • Unique way to represent, understand and inter-relate crystal

structures

  • Methodology to predict crystal structures

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We like to thank the following persons who helped us during the preparation

Family man:

  • Eline Schepers (daughter)
  • Freek Schepers (grandson)

Professor Leiden:

  • Daan IJdo (co-worker)
  • Guus Schippers (assistant)
  • Jan Reedijk (em prof Leiden)

Philips employee:

  • Frans Kools
  • George Blasse
  • Nol Broese van Groenou
  • Coen Rooijmans

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