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Prof Aletta Prinsloo

Prof Aletta Prinsloo
None
Department of Physics Academic Staff
Associate Professor

Contact Details
C1 Lab 127
011 559 2346
APK

​​​ 

Qualifications

  • 1990: BSc (Ed.), Rand Afrikaans University, Johannesburg.
    Majors: Chemistry, Physics, Mathematics, Education.
  • 1991: BSc (Hons), Experimental Physics, Rand Afrikaans University, Johannesburg.
  • 1992: MSc (Cum Laude), Physics, Rand Afrikaans University, Johannesburg.
    Dissertation: "Homogeniteit en stabiliteit van amorfe silikon dun lagies"
    Guide: Prof. R. Swanepoel
  • 1999: PhD, Physics, Rand Afrikaans University, Johannesburg.
    Thesis: "Spindigtheidsgolfgedrag van Cr-Ga en Cr-Si enkelkristalle"
    Supervisor: Prof. H.L. Alberts
    Co-supervisor: Prof. P. Smit

Fields of Specialisation

  • Magnetism
  • Solid StatePhysics
  • Thin films

Employment history

  • 1/1993 - 12/1994: 
    Position: Science teacher (permanent capacity)
    Institution: The National School for the Arts in Braamfontein
    Experience gained: Working with people on different levels
    Teaching in both English and Afrikaans
    Standard six to matric syllabus
  • 1/1995 - 12/1996: 
    Position: Science and Mathematics teacher (part-time capacity)
    Institution: The Adult Education Program at Victory Park Learning Centre
    Experience gained: Working with adults
    Adults completing standard nine and ten
  • 1/1997 - 7/1999:
    Position: Lecturer A
    Institution: Vista University, Department Physics (Soweto Campus)
    Responsible for: Lecturing Classical Mechanics (second year students)
    Lecturing Solid State Physics (third year students)
    Practical work for the above mentioned courses
  • 8/1999 - 12/1999: 
    Position: Lecturer 
    Institution: University of Witwatersrand, Department of Physics
    Responsible for: Lecturing a section of PHYS181 Mechanics (first year students)
    Tutorials and discussion group work for the PHYS181
  • 1/2000 - 12/2004: 
    Position: Senior Lecturer 
    Institution: Rand Afrikaans University, Department of Physics
    Responsible for: Training of MSc and PhD students.
    Lecturing Physics IC (first year biological students)
    Lecturing Physics 1B (Electricity & magnetism first year students)
    Lecturing Physics IIB (Classical Mechanics and Material Science)
    Lecturing Physics IIIA (Quantum Mechanics and Special Relativity)
    Practical experiments for Physics 1B.
    Practical experiments for Physics IIIA (Solid State and Nuclear Physics experiments)
    Lecturing Statistical Mechanics Honours Course
    Lecturing Solid State Physics Honours Course
    Projects for honours students.
  • 1/2005 - 3/2008: 
    Position: Senior Lecturer 
    Institution: University of Johannesburg, Department of Physics
    Responsible for: Training of MSc and PhD students.
    Lecturing Physics IIB (Classical Mechanics and Material Science)
    Practical experiments for Physics IIIA (Solid State and Nuclear Physics experiments)
    Lecturing Solid State Physics Honours Course
    Projects for honours students.
  • 3/2008 - current: 
    Position: Associate Professor
    Institution: University of Johannesburg, Department of Physics
    Responsible for: Training of MSc and PhD students.
    Lecturing Physics IIB (Classical Mechanics and Material Science)
    Practical experiments for Physics IIIA (Solid State and Nuclear Physics experiments)
    Lecturing Solid State Physics Honours Course
    Projects for honours students.
  • 1/2009 - 10/2012 
    Position: Deputy Head Physics Department APK
  •      Institution: University of Johannesburg, Department of Physics 
  • 11/2012 - present
  •       Position: Associate Professor
          Institution: University of Johannesburg, Department of Physics

Experience in Laboratories Abroad​

  • Laboratory Visited: IBM Almaden Research Center, San Jose, USA
    Period: 4/1/2001 to 11/2/2001
  • Laboratory Visited: Laboratoire de Magnetisme de Bretagne, 
    Centre National de la Reserche Scientifique Universite de Brest, France
    Period: 6/5/2005 to 27/5/2006
  • Laboratory Visited: Hitachi Almaden Research Center, San Jose, USA
    Period: 1/3/2006 to 31/5/2006
  • Laboratory Visited: Centre for Magnetic Recording, University of California San Diego (UCSD), USA
    Period: 10/5/2010 to 27/6/2010

NRF Rating

Evaluated in 2001 and placed in the Y category. 
Evaluated in 2007 and placed in the C3 category.

Awards

  • Best Physics III student at RAU during 1990.
  • SSPMS Conference Presentation Award for delivering the best presentation by a Ph.D. student at the 1996 SAIP Annual Conference in the session Solid State Physics and Material Science.
  • De Beers Diamond Research Laboratory Student Presentation Award for the most outstanding oral or poster presentation in the field of Solid State Physics and/or Material Science delivered at the 1998 SAIP Conference by a doctoral student at a South African Institution for tertiary education.
  • Labotec PhD student award for the best publication in the field of Solid State Physics and/or Material Science originating from a doctoral study presented to a South African Institution for Tertiary Education.

Supervised students receiving awards

  • KT Roro, whom I supervised for his MSc study, received the Student Presentation Award for the most outstanding poster presentation in the field of Solid State Physics and/or Material Science delivered at the 2004 SAIP Conference by a masters student at a South African Institution for tertiary education.
  • PhD student L Reddy was awarded "The most outstanding poster presentation in the field of Condensed Matter Physics and Material Science delivered at the Annual Conference of the South African Institute of Physics by a Doctoral Student at a South African Institute for Tertiary Education" at the 2005 SAIP Conference.
  • PhD student HA Derrett was awarded thrid prize for her presentation at "Die Studente Simposium van Die Suid-Afrikaanse Akademie vir Wetenskap en Kuns 2008".

Research Interests

The very interesting nature of the magnetism in Cr and Cr alloys are due to a large contribution of SDW origin that exists, contributing towards the physical properties of Cr based materials. It would be possible to tailor these alloys to attain specifically needed physical properties; such as certain thermal expansion characteristics, elastic constants or electrical resistivity, which can result in a variety of practical applications. This can only be done once the fundamental role of the SDW in these properties is understood. Currently these effects are not well understood and there is also a lack of theories that can describe the various situations. The purpose of current studies is to gain insight and understanding in the unique effects of the spin density wave on the physical properties of chromium and its alloys. This will be done through experimental work. Through collaborative work it may contribute to a microscopic theory, regarding the magnetoelastic behaviour of diluted Cr alloys.

In the literature there is renewed interest in the physical properties of dilute chromium alloys; particularly in the magnetic phase diagrams of the diluted alloys. These can be studied with various methods, such as ultrasonic wave velocities, thermal expansion and electrical resistivity measurements, as function of impurity concentration and temperature.

The anharmonic effects in single crystalline Cr alloys, is currently receiving a lot of interest in the literature. Many interesting properties were found in the study of the anharmonic effects in Cr alloys. Some of these alloys show a close relation between the dependence of their magnetic phase diagrams on electron concentration and pressure. Large negative Grüneisen parameters found in some Cr alloy single crystals, indicate the unusual property of a huge softening of the lattice, instead of stiffening, when the alloy is strained under hydrostatic pressure. The research project proposed, should give new and useful information in this regard, particularly on the role of the SDW-phonon interactions in Cr based alloys. This is needed for theoretical understanding of the processes. If these properties are well understood it can lead to a wide variety of applications that will be of importance to many industries making use of high-pressure facilities.

From recent developments it is clear that the pillar of 21st-century advanced technology is artificially made ordered material systems, of which metallic magnetic multi-layers and Cr alloys form a part. These types of structures show new and interesting physical phenomena, that gives potential for many technical advances in information storage and retrieval, integrated microwave circuits, optical communications and in the synthesis of new magnets for a variety of applications.

The use of Cr in magnetic multi-layers has brought Cr research to the forefront again, with a lot of interest in the role that Cr alloys play as spacer layers in magnetic multi-layer structures with giant magnetoresistance properties. The magnetic multi-layers are of interest, not only for their scientific value, but also for their technological applications. Since specific magnetic properties can be tailored in these artificially structured materials, it finds application in devices such as WAP-cellular telephones, digital cameras and digital storage media. Magnetic thin films are definitely an important topic that will carry magnetism into the 21st century. From a purely scientific point of view, the study of SDW effects in thin film Cr alloys is also of great interest. Such studies should give information regarding the dimensionality effects on the magnetic behaviour of Cr alloys.

Having a background in both thin film research (during my M.Sc.) and the magnetic properties of Cr (during my Ph.D.). Doing this type of research in the Department of Physics at UJ will make use of all the expertise gained through the years in thin film work as well as magnetism. This environment rich with extended knowledge is perfect for the training of postgraduate students.

 

Collaboration with Other Research Groups

  • Prof AM Strydom at University of Johannesburg, South Africa.
  • Dr AM Venter at Necsa, South Africa.
  • Dr CJ Sheppard at University of Johannesburg, South Africa 
  • Prof EE Fullerton at UCSD, San Diego, USA.
  • Dr D Spenato at UBO, Brest, France.
  • Dr D Dekadjevi at UBO, Brest, France.

Articles Emanating from Research​

  • A.R.E. Prinsloo, H.L. Alberts and P. Smit,
    High-pressure ultrasonic studies of a Cr-Ga alloy single crystal,
    Physica B237-238 (1997) 419-420
  • A.R.E. Prinsloo, H.L. Alberts and P. Smit,
    Spin-density-wave effects on the elasticity of Cr-Ga alloy single crystals,
    Journal of Physics: Condensed Matter 9 (1997) 9961-9983.
  • A.R.E. Prinsloo, H.L. Alberts and P. Smit,
    Acoustic-mode vibrational anharmonicity in Cr-Si alloy single crystals,
    Physical Review B56 (18) (1997) 11777-11785.

  • A.R.E. Prinsloo, H.L. Alberts and P. Smit,
    Non-linear acoustic properties of a Cr + 0.84 at.% Ga alloy single crystal through the Néel point, 
    Journal of Magnetism and Magnetic Materials 177-181 (1998) 1413-1414

  • A.R.E. Prinsloo, H.L. Alberts and P. Smit,
    Electrical transport properties of Cr-Si and Cr-Ga alloy single crystals,
    Journal of Physics: Condensed Matter 10 (1998) 2715-2725
  • A.R.E. Prinsloo, H.L. Alberts and P. Smit,
    Magnetoelasticity of Cr-Ga alloy single crystals at high pressures,
    Journal of Applied Physics, 85 (1999) 4747-4749
  • A.R.E. Prinsloo,
    Spindigtheidsgolfgedrag van Cr-Si- en Cr-Ga-allooi-enkelkristalle,
    SA Tydskrif vir Natuurweteenskap en Tegnologie, 19 (2000) 21-22
  • A.R.E. Prinsloo, O. Hellwig, E.E. Fullerton and H.L. Alberts,
    Characterization of epitaxial Cr + 0.35 at.% Ru thin films,
    Proceedings of the Microscopy Society of Southern Africa, (2001) 30
  • J.A.L. Lodya, H.L. Alberts and A.R.E. Prinsloo,
    High-pressure ultrasonic properties of spin-density wave Cr-Re alloy single crystals,
    Journal of Alloys and Compounds, 340 (2002) 27-38
  • A.M. Venter, A.R.E. Prinsloo and H.L. Alberts,
    Neutron diffraction studies of a Cr + 0.88 at.% Ga alloy single crystal,
    Applied Physics A, 74/7 (2002)
  • A.M. Venter, H.L. Alberts, A.R.E. Prinsloo and A.M. Dawe,
    Unusual magnetic effects in an itinerant electron anatiferromagnetic Cr-Pt alloys single crystal, 
    J. Appl. Phys. 93 (2003) 7269-7271
  • E.E. Fullerton, J.L. Robertson, A.R.E. Prinsloo, H.L. Alberts and S.D. Bader,
    Hysteretic spin-density-wave ordering in confined geometries, 
    Physical Review Letters 91 (2003) 237201-1 to 237201-4
  • A.R.E. Prinsloo, O, Nemoraoui, N. van den Berg, H.A. Derrett, C. Sheppard and H.L. Alberts,
    A study of the topography and transport properties of epitaxial Cr-Al thin films, 
    Microscopy Society of Southern Africa (MSSA), Proceedings 34 (2004) 23
  • H.A. Derrett, A.R.E. Prinsloo, H.L. Alberts and A.M. Venter,
    Magnetoelastic interactions in a Cr + 1.9 at.% Fe alloy single crystal,
    Journal of Magnetism and Magnetic Materials 272 (2004) 2084-2085
  • A.M. Venter, H.A. Derrett, A.R.E. Prinsloo and H.L. Alberts,
    Neutron diffraction investigation of the magnetic ordering in Cr + 1.9 at.% Fe, 
    Physica B 350 (2004) e71-e73
  • A.M. Venter, L. Reddy, H.L. Alberts and A.R.E. Prinsloo,
    Studies of magnetic order in Cr + 15 at.% Ru, 
    Physics B 385-386 (2006) 375-377 
  • K.T. Roro, A.R.E. Prinsloo and H.L. Alberts,
    Influence of V and Mn doping of the electrical transport properties of a Cr + 1.2 at.% Ga alloys,
    Journal of Alloys and Compounds 393 (2005) 16-25
  • A.R.E. Prinsloo, H.A. Derrett, H.L. Alberts and A.M. Venter,
    Magnetic effects in an itinerant electron antiferromagnetic Cr + 1.72 at.% Fe alloy single crystal,
    Journal of Applied Physics 99 (2006) 08F706-1 to 08F706-3 
  • L Reddy, HL Alberts, ARE Prinsloo and AM Venter,
    Antiferromagnetism in a Cr86Ru14 alloy,
    Journal of Alloys and Compounds 426 (2006) 83-92
  • L Reddy, HL Alberts, ARE Prinsloo and AM Strydom,
    Magnetic behaviour in the itinerant electron antiferromagnetic system Cr +14 at.% Ru doped with V, 
    Journal of Magnetism and Magnetic Materials 310 (2007) 1044-1045
  • L Reddy, HL Alberts, Am Strydom, ARE Prinsloo and AM Venter,
    Quantum Critical behaviour of the (Cr86V14)(1-x)Vx alloy system,
    Journal of Applied Physics 103 (2008) 07C903-1 to 07C903-3
  • B Li, HL Alberts, AM Strydom, BM Wu, ARE Prinsloo and Zh J Chen,
    Magnetic Properties of Cr-Fe-Mn alloys,
    Journal of Magnetism and Magnetic Materials 321 (2009) 61-73
  • HL Alberts, ARE Prinsloo and AM Strydom,
    Electrical transport properties of a Cr + 2.2 at.% Al single crystal,
    Journal of Magnetism and Magnetic Materials 322 (2010) 1092-1094
  • ARE Prinsloo, HA Derrett, O Hellwig, EE Fullerton, HL Alberts and N van den Berg,
    Influence of growth morphology on the Neel temperature of Cr-Ru thin films and heterostructures,
    Journal of Magnetism and Magnetic Materials 322 (2010) 1126-1129
  • CJ Sheppard, ARE Prinsloo, HL Alberts and AM Strydom,
    Evidence of a possible quantum critical point in a Cr-Si alloy doped with Mo,
    Journal of Applied Physics (109) April 2011

The magnetism group has a well equipped laboratory available for studying magnetic properties of materials, including the following: arc furnace for alloy preparations, crystal growing equipment (Bridgman, Czochralski, floating zone), spark cutting equipment, ultrasonic measuring equipment (phase comparison and pulse-echo-overlap methods) for ultrasonic velocity and attenuation measurements, equipment for accurate electrical resistivity, thermal expansion, magnetic susceptibility, thermal conductivity and Hall effect measurements, X-ray equipment, high pressure and low to high temperature equipment. Electron microprobe, XRD, SEM and AFM equipment, available at SPECTRAU (http://www.uj.ac.za/science/), are used regularly in our projects and neutron diffraction studies are done at Necsa.

Equipment Available



Illustration 1: arc furnace for alloy preparations

 

Illustration 2: crystal growing equipment (Bridgman, Czochralski, floating zone)

 

Illustration 3: spark cutting equipment 



Illustration 4 :ultrasonic measuring equipment (phase comparison and pulse-echo-overlap methods) for ultrasonic velocity and attenuation measurements 


Illustration 5: equipment for accurate electrical resistivity

 



Illustration 6: thermal expansion, magnetic susceptibility, thermal conductivity and Hall effect measurements high pressure (0-14 kbar)




Illustration 7: SEM equioment




Illustration 8:  X-ray equipment