Technische Physik

Prof. Rudolf Gross

Forschungsgebiet

The research activities of the Walther-Meißner-Institute are focused on low temperature solid-state and condensed matter physics. The research program is devoted to both fundamental and applied research and also addresses materials science, thin film and nanotechnology aspects. With respect to basic research the main focus of the WMI is on

  • superconductivity and superfluidity,
  • magnetism, spin transport, and spin caloritronics,
  • quantum phenomena in mesoscopic systems and nanostructures,
  • and the general properties of metallic systems at low and very low temperatures.

The WMI also conducts applied research in the fields of

  • solid-state quantum information processing systems,
  • superconducting and spintronic devices,
  • oxide electronics,
  • multi-functional and multiferroic materials,
  • and the development of low and ultra low temperature systems and techniques.

With respect to materials science, thin film and nanotechnology the research program is focused on

  • the synthesis of superconducting and magnetic materials,,
  • the single crystal growth of oxide materials,
  • the thin film technology of complex oxide heterostructures including multi-functional and multiferroic material systems,
  • the fabrication of superconducting, magnetic, and hybrid nanostructures,
  • and the growth of self-organized molecular ad-layers.

The WMI also develops and operates systems and techniques for low and ultra-low temperature experiments. A recent development are dry mK-systems that can be operated without liquid helium by using a pulse-tube refrigerator for precooling. Meanwhile, these systems have been successfully commercialized by the company VeriCold Technologies GmbH at Ismaning, Germany, which meanwhile has been acquired by Oxford Instruments. As further typical examples we mention a nuclear demagnetization cryostat for temperature down to below 100µK, or very flexible dilution refrigerator inserts for temperatures down to about 20mK fitting into a 2inch bore. These systems have been engineered and fabricated at the WMI. Within the last years, several dilution refrigerators have been provided to other research groups for various low temperature experiments. The WMI also operates a helium liquifier with a capacity of more than 150.000 liters per year and supplies both Munich universities with liquid helium. To optimize the transfer of liquid helium into transport containers the WMI has developed a pumping system for liquid helium that is commercialized in collaboration with a company.

Adresse/Kontakt

Walther-Meißner-Straße 8
85748 Garching b. München
+49 89 289 14202
Fax: +49 89 289 14206

Mitarbeiterinnen und Mitarbeiter der Arbeitsgruppe

Professorinnen und Professoren

Mitarbeiterinnen und Mitarbeiter

Lehrangebot der Arbeitsgruppe

Lehrveranstaltungen mit Beteiligung der Arbeitsgruppe

Ausgeschriebene Angebote für Abschlussarbeiten an der Arbeitsgruppe

Engineering Magnetization Dynamics in a Magnetic Insulator

In magnetic resonance, a high frequency magnetic drive field is employed to excite the precessional motion of the magnetization of a magnet. Besides this fundamental excitation, where all spins are precessing in an orchestrated, collective motion, higher order magnetic resonance modes can be excited and investigated using broadband microwave spectroscopy techniques. Furthermore, as these properties rely on the „magnetic“ bandstructure of the material, they can also be tailored using nano-fabrication methods yielding engineered magnetic structures such as waveguides or resonators.

We are looking for a talented master student, who is eager to explore the different possibilities for tailoring the dynamic magnetic properties of yttrium iron garnet (YIG). The goal of your thesis is to design, fabricate and investigate tailored magnetic bandstructures in YIG, in particular also in freely suspended films. The thesis work involves simulation of the (magnetic) structures, advanced nano-patterning, as well as high frequency spectroscopy of the fabricated devices.

Contact: Hans.Huebl@wmi.badw.de, Mathias.Weiler@wmi.badw.deRudolf.Gross@wmi.badw.de

geeignet als
  • Masterarbeit Physik der kondensierten Materie
  • Masterarbeit Applied and Engineering Physics
Themensteller(in): Rudolf Gross
Magnetische Quantenoszillationen in dem antiferromagnetischen Supraleiter kappa-(BETS)2FeBr4

One of the challenging goals in modern materials science is the rational design of multifunctional molecular compounds that combine technologically useful features such as electrical conductivity and magnetism. A promising strategy is to create hybrid organic/inorganic crystals comprising two functional sublattices exhibiting distinct properties. Recently, several compounds have been synthesized in which the metallic conductivity is provided by organic layers sandwiched between inorganic layers responsible for magnetic ordering. The goal of the present Master thesis is to inverstigate the interplay between the magnetic and conducting subsystems in the organic superconductor k-(BETS)2FeBr4 in vicinity of the antiferromagnetic quantum phase transition. Quantum oscillations of magnetization and interlayer resistivity in strong magnetic fields will be used to probe the electronic properties of this material.

Techniques: Strong magnetic fields; magnetotransport; magnetic torque; cryogenic (liquid 4He and 3He) techniques.

Physics: Electronic correlations; magnetic quantum oscillations; antiferromagnetism.

Contact: Mark.Kartsovnik@wmi.badw.deRudolf.Gross@wmi.badw.de

geeignet als
  • Masterarbeit Physik der kondensierten Materie
Themensteller(in): Rudolf Gross
Raman-Streuung an Phononen in YBa2Cu3O6+x in der Nähe von Zwillingsgrenzen
Close to twin and grain boundaries the crystal lattice is expected to be strained. The strain fields extend over several unit cells. In some materials new properties such as superconductivity are found in this range which is intended to be scrutinized by confocal and tip-enhanced Raman spectroscopy. To this end the apex phonon of YBa2Cu3O6+x (c-axis vibration of the oxygen atoms above the CuO2 plane) will be studied in the vicinity of twin and grain boundaries using light scattering. If the local resolution of confocal Raman scattering is insufficient, the near field effect of metallic tips shall be exploited. Eventually, the tips have to be prepared freshly. The work includes a thorough introduction to spectroscopy as well as low-temperature and ultra-high vacuum (UHV) methods.
geeignet als
  • Masterarbeit Physik der kondensierten Materie
  • Masterarbeit Applied and Engineering Physics
Themensteller(in): Rudolf Hackl
Tunnel- und Raman-Spektroskopie an Kuprat-Supraleitern
In superconductors on CuO2 basis (cuprates) the fundamental questions as to the relevant energy scales such as the gap in the superconducting state or the pseudo-gap above the superconducting transition temperature Tc as well as their interrelation remain a tantalizing open problem. This is highlighted by the discrepancies between the different types of spectroscopies sensitive to electronic excitations such as photoemission, tunneling, infrared of Raman spectroscopy. Tunneling spectroscopy has enough resolution to demonstrate the spatial variation of the energy scales. Raman spectroscopy shows a dependence of the energy scales on impurities and strain. For addressing this problem it is intended to study tunneling and Raman spectra at the identical location of selected samples and to analyze the data simultaneously. The analysis will be performed in collaboration with theorists at Stanford University, CA, USA. The work includes a thorough introduction to spectroscopy as well as low-temperature and ultra-high vacuum (UHV) methods.
geeignet als
  • Masterarbeit Physik der kondensierten Materie
  • Masterarbeit Applied and Engineering Physics
Themensteller(in): Rudolf Hackl
Untersuchung von Magnetismus und Supraleitung in unterdotiertem YBa2Cu6O6+x
geeignet als
  • Masterarbeit Physik der kondensierten Materie
Themensteller(in): Rudolf Hackl
Untersuchung von Phononen in magnetisch entzwillingtem EuFe2As2
Phonons are quantized lattice vibrations that couple to basically all excitations in a solid. In iron-based compounds for instance, several phonons couple to the electronic structure which is modified by the stripe-like magnetic order at low temperature. This was studied successfully in BaFe2As2. As a caveat, these samples need to be de-twinned mechanically, and the necessary strain has also an impact on the phonons entangling the effects of strain and magnetic order. This problem can be overcome by using EuFe2As2 which can be de-twinned in moderate magnetic fields and then stays single-domain even after switching off the field. This facilitates a “clean” experiment which helps answering the question as to the driving force behind magnetism, structural distortions, and superconductivity in the iron-based compounds. It is planned to study the phonons of EuFe2As2 (Jannis Maiwald and Philipp Gegenwart, University of Augsburg) at various doping levels and compare the results to theoretical predictions. For the theory work there is a long-standing collaboration with theory groups in Frankfurt/Main and Washington, D.C., USA. The work includes an introduction to spectroscopy, low-temperature, and high-field techniques.
geeignet als
  • Masterarbeit Physik der kondensierten Materie
  • Masterarbeit Applied and Engineering Physics
Themensteller(in): Rudolf Hackl

Abgeschlossene und laufende Abschlussarbeiten an der Arbeitsgruppe

Engineering interfacial spin-orbit torques
Abschlussarbeit im Masterstudiengang Physik (Physik der kondensierten Materie)
Themensteller(in): Rudolf Gross
Ablation Loading and Coherent Control of Strontium Ions in a Linear Paul Trap
Abschlussarbeit im Masterstudiengang Physik (Physik der kondensierten Materie)
Themensteller(in): Rudolf Gross
Magnetic and electronic excitations in underdoped YBCO
Abschlussarbeit im Masterstudiengang Physik (Physik der kondensierten Materie)
Themensteller(in): Rudolf Hackl
Nanomechanics coupled to superconducting quantum circuits
Abschlussarbeit im Masterstudiengang Physics (Applied and Engineering Physics)
Themensteller(in): Hans-Gregor Hübl
Investigation of magnetoelastic properties of magnetoresistive sensor structures
Abschlussarbeit im Masterstudiengang Physics (Applied and Engineering Physics)
Themensteller(in): Rudolf Gross
Prediction of a power potential duration for a high voltage battery in electromobility
Abschlussarbeit im Masterstudiengang Physics (Applied and Engineering Physics)
Themensteller(in): Rudolf Gross

Kondensierte Materie

Wenn Atome sich zusammen tun, wird es interessant: Grundlagenforschung an Festkörperelementen, Nanostrukturen und neuen Materialien mit überraschenden Eigenschaften treffen auf innovative Anwendungen.