Magnetisation of isolated single crystalline Fe-nanoparticles measured by a ballistic Hall micro-magnetometer

2000 ◽  
Vol 10 (2) ◽  
pp. 259 ◽  
Author(s):  
L. Theil Kuhn ◽  
A.K. Geim ◽  
J.G.S. Lok ◽  
P. Hedegård ◽  
K. Ylänen ◽  
...  
2011 ◽  
Vol 2 ◽  
pp. 47-56 ◽  
Author(s):  
Armin Kleibert ◽  
Wolfgang Rosellen ◽  
Mathias Getzlaff ◽  
Joachim Bansmann

Background: Magnetic nanostructures and nanoparticles often show novel magnetic phenomena not known from the respective bulk materials. In the past, several methods to prepare such structures have been developed – ranging from wet chemistry-based to physical-based methods such as self-organization or cluster growth. The preparation method has a significant influence on the resulting properties of the generated nanostructures. Taking chemical approaches, this influence may arise from the chemical environment, reaction kinetics and the preparation route. Taking physical approaches, the thermodynamics and the kinetics of the growth mode or – when depositing preformed clusters/nanoparticles on a surface – the landing kinetics and subsequent relaxation processes have a strong impact and thus need to be considered when attempting to control magnetic and structural properties of supported clusters or nanoparticles. Results: In this contribution we focus on mass-filtered Fe nanoparticles in a size range from 4 nm to 10 nm that are generated in a cluster source and subsequently deposited onto two single crystalline substrates: fcc Ni(111)/W(110) and bcc W(110). We use a combined approach of X-ray magnetic circular dichroism (XMCD), reflection high energy electron diffraction (RHEED) and scanning tunneling microscopy (STM) to shed light on the complex and size-dependent relation between magnetic properties, crystallographic structure, orientation and morphology. In particular XMCD reveals that Fe particles on Ni(111)/W(110) have a significantly lower (higher) magnetic spin (orbital) moment compared to bulk iron. The reduced spin moments are attributed to the random particle orientation being confirmed by RHEED together with a competition of magnetic exchange energy at the interface and magnetic anisotropy energy in the particles. The RHEED data also show that the Fe particles on W(110) – despite of the large lattice mismatch between iron and tungsten – are not strained. Thus, strain is most likely not the origin of the enhanced orbital moments as supposed before. Moreover, RHEED uncovers the existence of a spontaneous process for epitaxial alignment of particles below a critical size of about 4 nm. STM basically confirms the shape conservation of the larger particles but shows first indications for an unexpected reshaping occurring at the onset of self-alignment. Conclusion: The magnetic and structural properties of nanoparticles are strongly affected by the deposition kinetics even when soft landing conditions are provided. The orientation of the deposited particles and thus their interface with the substrate strongly depend on the particle size with consequences regarding particularly the magnetic behavior. Spontaneous and epitaxial self-alignment can occur below a certain critical size. This may enable the obtainment of samples with controlled, uniform interfaces and crystallographic orientations even in a random deposition process. However, such a reorientation process might be accompanied by a complex reshaping of the particles.


Nano Letters ◽  
2011 ◽  
Vol 11 (4) ◽  
pp. 1641-1645 ◽  
Author(s):  
Lise-Marie Lacroix ◽  
Natalie Frey Huls ◽  
Don Ho ◽  
Xiaolian Sun ◽  
Kai Cheng ◽  
...  

Nanoscale ◽  
2014 ◽  
Vol 6 (9) ◽  
pp. 4852-4856 ◽  
Author(s):  
Sen Zhang ◽  
Guangming Jiang ◽  
Gabriel T. Filsinger ◽  
Liheng Wu ◽  
Huiyuan Zhu ◽  
...  

We report a facile halide ion (Cl− or Br−) mediated synthesis of Fe nanoparticles (NPs) by thermal decomposition of Fe(CO)5.


Author(s):  
Joseph D. C. Peng

The relative intensities of the ED spots in a cross-grating pattern can be calculated using N-beam electron diffraction theory. The scattering matrix formulation of N-beam ED theory has been previously applied to imperfect microcrystals of gold containing stacking disorder (coherent twinning) in the (111) crystal plane. In the present experiment an effort has been made to grow single-crystalline, defect-free (111) gold films of a uniform and accurately know thickness using vacuum evaporation techniques. These represent stringent conditions to be met experimentally; however, if a meaningful comparison is to be made between theory and experiment, these factors must be carefully controlled. It is well-known that crystal morphology, perfection, and orientation each have pronounced effects on relative intensities in single crystals.The double evaporation method first suggested by Pashley was employed with some modifications. Oriented silver films of a thickness of about 1500Å were first grown by vacuum evaporation on freshly cleaved mica, with the substrate temperature at 285° C during evaporation with the deposition rate at 500-800Å/sec.


2013 ◽  
Vol 58 (2) ◽  
pp. 142-150 ◽  
Author(s):  
A.V. Sachenko ◽  
◽  
V.P. Kostylev ◽  
V.G. Litovchenko ◽  
V.G. Popov ◽  
...  

2014 ◽  
Vol 29 (11) ◽  
pp. 1199
Author(s):  
LI Xiao-Shuai ◽  
WANG Zeng-Mei ◽  
ZHU Ming-Fang ◽  
WANG Shan-Peng ◽  
TAO Xu-Tang ◽  
...  
Keyword(s):  

2003 ◽  
Vol 762 ◽  
Author(s):  
Hwang Huh ◽  
Jung H. Shin

AbstractAmorphous silicon (a-Si) films prepared on oxidized silicon wafer were crystallized to a highly textured form using contact printing of rolled and annealed nickel tapes. Crystallization was achieved by first annealing the a-Si film in contact with patterned Ni tape at 600°C for 20 min in a flowing forming gas (90 % N2, 10 % H2) environment, then removing the Ni tape and further annealing the a-Si film in vacuum for2hrsat600°C. An array of crystalline regions with diameters of up to 20 μm could be formed. Electron microscopy indicates that the regions are essentially single-crystalline except for the presence of twins and/or type A-B formations, and that all regions have the same orientation in all 3 directions even when separated by more than hundreds of microns. High resolution TEM analysis shows that formation of such orientation-controlled, nearly single crystalline regions is due to formation of nearly single crystalline NiSi2 under the point of contact, which then acts as the template for silicide-induced lateral crystallization. Furthermore, the orientation relationship between Si grains and Ni tape is observed to be Si (110) || Ni (001)


Author(s):  
Frank Bergner ◽  
Michael Schaper ◽  
Ralf Hammer ◽  
Manfred Jurisch ◽  
Andre Kleinwechter ◽  
...  

1991 ◽  
Author(s):  
David E. Luzzi ◽  
David P. Pope ◽  
Vaclay Vitek

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