Category Archives: Events

Seminar Series by Prof. Kannan Krishnan – 3

Department of Materials Engineering
Indian Institute of Science

is pleased to invite you to the seminar on

Magnetism, microstructure and materials characterization
by
Prof. Kannan M. Krishnan
Brahm Prakash Visiting Chair
Department of Materials Engineering
Indian Institute of Science, Bangalore
and
Department of Materials Sciences & Engineering, and Physics
University of Washington
Seattle, USA

at 3:30 p.m.
on (Date to be announced)
in the Lecture Theatre, Department of Materials Engineering.

Abstract

Magnetic materials, subtle in their manifestation, are electronically driven with their origin in the Pauli exclusion principle and the existence of electron spin. They are known for a variety of both classical and quantum-mechanical effects, arising from both short- and long-range forces, and are widely associated with “microstructure” or the morphological arrangements of magnetic moments (domains), as well as phases, grains, or individual atoms themselves. These are, in part, the reason for the richness in properties and technological applications encountered in magnetic systems. These are also, in part, why the magnetic behavior of materials is poorly understood [1].

In this talk, with a materials science structure-property-processing perspective, and drawing on our work on a wide range of materials [2] (nanoparticles [3], doped semiconducting oxides [4] and epitaxially grown metallic heterostructures [5]), I will describe their behavior at relevant length scales. Advanced characterization techniques using transmission electron microscopy (electron energy-loss spectroscopy, holography [6], energy-filtered imaging [7], atomic column-by-column z-contrast imaging) and synchrotron radiation [8] (x-ray absorption spectroscopy, x-ray magnetic circular dichroism and x-ray magnetic reflectivity [9]) are integral to these studies.

Specific topics to be addressed include:

  • Self-assembly [10], inter-particle magnetic interactions/order [11] and “memory” in magnetic nanoparticle systems
  • Defect-mediated ferromagnetism [12] in transition-metal-doped dilute magnetic semiconductors
  • Exchange-bias [13], asymmetric magnetic reversal [14] and the role of buried interfaces [15] in epitaxial heterostructures [16].

1. Kannan M. Krishnan, Fundamentals and applications of magnetic materials, Oxford University Press, 820pp, ISBN 9780199570447 (Available, Summer 2016)

2. Kannan M. Krishnan et al, Jour. Mat. Sci. 41, 793–815 (2006)

3. V. F. Puntes, Kannan M. Krishnan and P.A. Alivisatos, Science, 291, 2115-2117 (2001).

4. K. G. Roberts, M. Varela, S. Rakshev, S. Pantelides, S. J. Pennycook and Kannan M. Krishnan, Phys, Rev. B 78, 014409 (2008)

5. Wei Zhang and Kannan M. Krishnan, “Epitaxial exchange-bias systems: from fundamentals to spin-orbitronics”, Materials Science & Engineering – R: Reports (in press)

6. Y. Takeno, … Kannan M. Krishnan, Appl. Phys. Lett. 105, 183102 (2014)

7. W. Grogger, B. Schaffer, Kannan M. Krishnan and F. Hofer, Ultramicroscopy 96, 481-489 (2003).

8. G. Srajer et al, Jour. Mag. Mag. Mat. 307, 1-31 (2006)

9. Sebastian Brück et al, Phys. Rev. B 81 134414 (2010)

10. Y. Bao, M. Beerman and Kannan M. Krishnan, Jour. of Mag. Mag. Mat., 272-276, Supp1, E1367-E1368 (2004)

11. Y. Gao, Y. Bao, A. B. Pakhomov, Daisuke Shindo and Kannan M. Krishnan, Phys. Rev. Lett., 96, 137205 (2006)

12. K.A. Griffin, A.B. Pakhomov, C.M. Wang, S.M. Heald, Kannan M. Krishnan, Phys. Rev. Lett., 94, 157204 (2005)

13. W. Zhang and Kannan M. Krishnan, Jour. Micromech. & Microeng. 24, 093001 (2014)

14. P. Blomqvist, Kannan. M. Krishnan and H. Ohldag, Phys. Rev. Lett., 94, 107203 (2005)

15. S. Bruck, E. Goering, G. Schutz, X. Ji and Kannan M. Krishnan, Phys. Rev. Lett. 101, 126402 (2008)

16. This work was supported by US-Grants DOE DE-AC03-76SF00098, DoE/BES ER-45987, NSF/DMR #0203069, NSF/DMR #0322729, NSF/ECS #0224138, NSF/DMR #0315460

Seminar Series by Prof. Kannan Krishnan – 2

Department of Materials Engineering
Indian Institute of Science

is pleased to invite you to the seminar on

Magnetism on the mesoscale: Nanotechnology, Lithography, Information Storage and Logic
by
Prof. Kannan M. Krishnan
Brahm Prakash Visiting Chair
Department of Materials Engineering
Indian Institute of Science, Bangalore
and
Department of Materials Sciences & Engineering, and Physics
University of Washington
Seattle, USA

at 3:30 p.m.
on 13.1.2016 (Wednesday)
in the Lecture Theatre, Department of Materials Engineering.

Abstract

There has been a renaissance in magnetism and magnetic materials research on the nanometer length scale, largely driven by size-dependent scaling laws, exchange, proximity and interface effects, advances in fabrication [1,2], and their demonstrated impact in information technologies.

I will begin this lecture with a brief discussion of criteria that define Nanoscience and Nanotechnology and illustrate them with characteristic length scales and size effects that make magnetism ideal, not only for fundamental investigations, but also technological developments on this length scale.

In the second part of this lecture, I will present recent developments in lithographic fabrication of nanoscale elements, emphasizing the facile, low-cost method of nanoimprint lithography. I will then illustrate some fundamental magnetic studies of competing anisotropies in epitaxial grown nanowire arrays [3], manipulating domain wall reversal by shape anisotropy [4] and the properties of three-dimensional “sombrero” shaped s structures [5,6].

Next, I will address the current status of magnetic recording media and discuss the development of next-generation bit-patterned media [7], proposed to sustain the current growth rate of recording densities. I will conclude with a discussion of a novel concept of building Boolean logic gates [8], called magnetic quantum cellular automata, based purely on dipolar coupling of magnetic arrays [9].

1. Wei Zhang and Kannan M. Krishnan, “Epitaxial patterning of thin films: conventional lithographies and beyond”, Jour. Micromech. & Microeng. 24, 093001 (2014)

2. Y. Bao, T. Wen, A.C. Samia, A.P. Khandhar, and Kannan M. Krishnan, “Magnetic Nanoparticles: Materials Engineering and Emerging Applications in Lithography and Biomedicine”, Jour Mater. Sci. , 51, 513-553 (2016)

3. Wei Zhang, Mark E. Bowden and Kannan M. Krishnan, “Nanoimprint-lithography patterned epitaxial Fe nanowire arrays with misaligned magnetocrystalline and shape anisotropies”, Jour. Appl. Phys. 113 17B502 (2013)

4. W. Zhang, D. N Weiss and Kannan M Krishnan, “ Thermal nanoimprint process for high-temperature fabrication of epitaxial exchange-biased metallic nanostructures”, Jour. Micrmech. Microeng. 21, 045204 (2011)

5. Byung Seok Kwon, Wei Zhang and Kannan M. Krishnan, “Sombrero-shaped Fe3O4 nanoelements with tunable out-of-plane and in-plane magnetization components fabricated by nano-imprint lithography”, Jour. Appl. Phys. 115, 17B506 (2014

6. Byung-Seok Kwon, Wei Zhang and Kannan M. Krishnan, “Direct release of Bio-compatible Sombrero-shaped Magnetite Nanoparticles via Nanoimprint Lithography”, Advanced Materials – Interfaces, 2, 1400511 (2015)

7. Zheng Li, Wei Zhang+ and Kannan M. Krishnan, “Large-area patterning of sub-100 nm L10 FePt dots array”, AIP Advances. 5, 087165 (2015)

8. Zheng Li and Kannan M. Krishnan, “Misalignment-free signal propagation in nanomagnet arrays and logic gates with 45°-clocking field”, Jour. Appl. Phys. 115, 17E502 (2014)

9. This work was supported by US-DOE/BES Grant ER45987 and US-NSF Grant DMR-1063489

Seminar Series by Prof. Kannan Krishnan – 1

Department of Materials Engineering
Indian Institute of Science

is pleased to invite you to the seminar on

From materials to medicine: a sp↑n through recent developments in imaging, therapy and diagnostics
by
Prof. Kannan M. Krishnan
Brahm Prakash Visiting Chair
Department of Materials Engineering
Indian Institute of Science, Bangalore
and
Department of Materials Sciences & Engineering, and Physics
University of Washington
Seattle, USA

at 3:30 p.m.
on 12.1.2016 (Tuesday)
in the Lecture Theatre, Department of Materials Engineering.

Abstract

The Néel relaxation of magnetic nanoparticles (MNP), subject to alternating magnetic fields in solution, depends exponentially on the size of their magnetic core, whilst the complementary Brownian relaxation mechanism depends critically on their hydrodynamic volume [1,2]. Recent developments in the synthesis [3] and applications [4] of highly monodisperse and phase-pure magnetite nanoparticles, with negligible toxicity [5] and favorable biodistribution [6], allows for reproducible control of the former, even in “harsh” biological environments, enabling novel imaging [7,8,9], spectroscopic [10] and therapeutic1112 modalities, under ac excitations. With appropriate functionalization of the monodisperse cores, and utilizing the magnetic relaxation, it also allows for the development of sensitive, relaxation based assays13 for the detection of biomolecules associated with various diseases.

In this multidisciplinary talk, beginning with the physics of magnetic relaxation under ac excitation, I will describe the chemical synthesis, phase optimization, surface functionalization, and development of optimized nanoparticle tracers with magnetic properties tailored for the unique physics of Magnetic Particle Imaging –– an emerging tracer-based whole body imaging technique with no ionizing radiation, and present recent results in phantom and in vivo imaging of animal models for cardiovascular disease and molecular imaging of cancer. I will also present details of newly designed assays, using magnetic particle spectroscopy, for the detection of proteases that are closely linked to malignant phenotypes of different solid tumors and conclude with an outlook of opportunities that abound for continued research in this exciting field [14].

1. Kannan M. Krishnan, IEEE Trans. Mag. 46, 2523-2558 (2010)

2. C. Kuhlmann, A. P. Khandhar, R. M. Ferguson, S. Kemp, T. Wawrzik, M. Schilling, Kannan M. Krishnan and F. Ludwig, IEEE Trans. Mag. 51, 6500504 (2015)

3. R. Hufschmid, H. Arami, R. M. Ferguson, M. Gonzales, E. Teeman, L. Brush, N. Browning and Kannan M. Krishnan, Nanoscale, 7, 11142 (2015)

4. Y. Bao, T. Wen, A.C. Samia, A.P. Khandhar, and Kannan M. Krishnan, Jour Mater. Sci., 51, 513-553 (2016)

5. H. Arami, A. Khandhar, D. Liggitt and Kannan M. Krishnan, Chem. Soc. Rev. 44, 8576 (2015)

6. H. Arami, A. P. Khandhar, A. Tomitaka and Kannan M. Krishnan, Biomaterials 52, 251 (2015)

7. B. Gleich & J. Weizenecker, Nature 435, 1214 (2005).

8. R.M. Ferguson, A.P. Khandhar, H. Arami, E.U. Saritas, L.R. Croft, P.W. Goodwill, A. Halkola, J. Rahmer, J. Borgert, S.M. Conolly and Kannan M. Krishnan, IEEE Trans. Med. Imag. 34, 1077 (2015)

9. A. Tomitaka, S. Gandhi, H. Arami and Kannan M. Krishnan, Nanoscale 7, 16890-16898 (2015).

10. S. A. Shah, D.B. Reeves, R.M. Ferguson, J.B. Weaver, and Kannan M. Krishnan, Phys. Rev. B92, 094438 (2015)

11. A. Khandhar, R. Matthew Ferguson, Julian A. Simon and Kannan M. Krishnan, Jour. Biomedical Materials Research, Part A, 100A, 728-737 (2012)

12. S. Kalale, R. Narain and Kannan M. Krishnan, Jour. Mag. Mag. Mat. 321, 1377-1380 (2009)

13. S. Gandhi, H. Arami, Kannan M. Krishnan, Proc. Nat. Acad. Sci., (submitted)

14. This work was supported by US-NIH Grants 1RO1EB013689-01/NIBIB, 1R41EB013520-01, and 2R42EB013520-02A1.

Alumni Reunion on 25 June 2015

Over 40 of our alumni will be visiting the Institute for the IISc Alumni Global Conference, which starts with a pre-conference event for the alumni to visit their departments in the afternoon of Thursday, the 25th of June, 2015.

The Alumni Reunion in our Department starts at 2:30 p.m. in the Lecture Theatre with alumni introductions, and short presentations by Prof. Vikram Jayaram, Chairman, and Prof. S. Ranganathan.

This will be followed by High Tea in the courtyard for informal interactions between the alumni and our faculty and students. Alumni will also be taken on a tour of the Department and the Institute.

PhD Defence by Ms. Soumya S. Bhat (11.30am, 20 Mar 2015)

Name of student : Ms. Soumya S. Bhat

Title : “First-principles studies of point defects and phase transformations in materials”

Faculty Advisors : Prof. U. Ramamurty
Prof. Umesh V. Waghmare (Theoretical
Sciences Unit, JNCASR)

Date : Friday, 20th March 2015

Time : 11:30 AM

Venue : Multi Media Class Room (MMCR,
First Floor), CeNSE

Departmental sports day (14th March 2015)

Departmental sports day is scheduled on this Saturday (14th March 2015)
from 8 am onwards at Gymkhana football ground.

The list of events to be held is mentioned below,
100 meters
4 x 100 meters relay
400 meters
Futsal (Mini football)
Box cricket
3 game event
Badminton
Table Tennis
Slow Cycling
Musical Chair
Tug of War

Exciting prizes for winners. All are cordially invited.
Do register for the events beforehand.
Registration link is given below
Sports Day registration

28th Annual Students’ Symposium, 22-23 January 2015

Preamble
The First edition of the Annual Students Symposium was held in the academic year 1987-88. The novel initiative was formulated by Gouthama, presently a faculty member at IIT Kanpur. Traditionally the aim, with which this event was envisaged, was to create a platform for the students of this department to interact by presenting and sharing their research amongst themselves. With time, and with the induction of undergraduates, this event has broadened to include the new members of this department, as well as try to familiarise its students with the research done elsewhere. This year, we take pride in ourselves by maintaining the legacy of this Annual Students’ Symposium for 28 years.

Message from Convenors
Times of festivity are times to be relished. For a person married to the technical way of life, there can be nothing more joyful than the moment when he can speak about his work to an appreciative audience. This is the moment for which he waits patiently, just like one waits for the arrival of a festive season.

One such moment, for which the students of this department wait every year, is the Annual Students’ Symposium. Happening for the last 27 years, the aim of this symposium has been to present a platform for the research students of this department to interact, by presenting their ideas, amongst themselves. It also doubles up its responsibilities and enlightens the students about research taking place elsewhere through talks by dignitaries invited from various academies and industries.

The 28th Annual Students’ Symposium will be held on 22nd and 23rd January, 2015. It gives us immense pleasure to be a part of the organising team of the students’ symposium. We hope the effort that we put in bears fruit through a successful conduction of the symposium, and may this symposium be a pleasurable moment for the students of the department as well.

Convenors,
Subham Mridha
Rajib Kalsar

International Workshop on Iron and Steelmaking (IWIS-2014) from December 3 to 5, 2014

Dear Colleagues

We are happy to inform you that we are organizing an International Workshop on Iron and Steelmaking (IWIS-2014) from December 3 to 5, 2014 as a tribute to commemorate the singular contributions made by our colleague the late Professor K. P. Abraham, to the field of physical chemistry of iron and steelmaking. As India is poised to make major strides in steel production, we hope this workshop is a timely event. We are attaching the Workshop Circular with this e-mail. We are fortunate to have some leading luminaries of the world in the areas of iron and steel making as speakers to this workshop.

The Department of Materials Engineering has made valuable contributions in this area over the past few decades. We request you to give wide publicity to this event. We will keep you informed about the progress of this workshop.  For further information please visit the workshop Web site: 
(http://materials.iisc.ernet.in/~iwis2014/).

Thanking you and with warm regards

Conveners

(Govind S. Gupta, S. Subramanian, T.R.R. Rao and S. Seetharaman)