Tailoring AlFe B Magnetism-Structure Relationships for ...
Graduate Student Category: Engineering and Technology Degree Level: Ph.D. Abstract ID# 1346
Elemental Substitution for Designing ‘Cool’ New Materials:
Tailoring AlFe2B2 Magnetism-Structure Relationships for Magnetocaloric Applications Brian Lejeune & L.H. Lewis, Department of Chemical Engineering, Northeastern University
Abstract:
A new family of lightweight, inexpensive materials based on the composition AlFe2B2 with potential applications for sensors and magnetocaloric cooling is investigated.1 In particular, the magnetocaloric effect (MCE) can be utilized for CFC-free magnetic refrigeration to achieve 30-50% higher efficiencies than compression cooling, potentially reducing energy usage in a 200 billion dollar per year industry.2 The MCE is the reversible adiabatic temperature change of a magnetic material upon the application or removal of a magnetic field and is amplified in materials undergoing magnetostructural phase changes.2 In this work investigation of the magnetostructural phase transition in AlFe2B2 allows correlation between magnetic behavior, composition and structural properties. In this manner the phase change behavior may be tuned to different temperature and magnetic field regimes. Results indicate that composition alters the magnetic transition temperature of the system. Extending the range of transition temperatures achievable in the AlFe2B2 family of materials makes this a more versatile system for proposed applications.
Motivation: Novel materials support rising energy demand
Global energy demand (PJ)
Increased demand for global heating/cooling3
AlFe2B2 structure
AlFe2B2: New material for applications Inexpensive, produced from abundant elements Magnetic phase transition @ room temperature
Magnetic refrigerator
Cooling
Magnetized
Fe-B layer
Magnetic actuator
Magnetic field Heating Cooling
Al layer
Crystal
Heating
b
Demagnetized Mag. field
15% of worldwide energy usage is from cooling3
http://goo.gl/I89jlK
http://goo.gl/9Iqgi6
Jeitschuko, W. Acta Crystallogr (1969).
Results: AlT2B2 (T = Fe, Mn, Co, Ni) shows promise for magnetic refrigeration & sensing Response evaluated using the Magnetocaloric Effect (MCE) Adiabatic temperature change (ΔTad) of a material subjected to a variation in magnetic field ΔTad ≈ -(T/ CH )*∆Sm
Orientational relationship between structure and magnetism
Evidence of AlFe2B2 coupled structural and magnetic transition
Al13Fe4
Al
T = Temp. (K) CH = Heat capacity (J/kg-K) ΔSm = Mag. entropy change (J/kg-K)
Largest magnetocaloric effect near transition temperature
AlFe2B2
Strong correlation between Fe-B chains & magnetic response
200 micron
Conserved unit cell volume through transition
AlFe1.9T0.1B2 elemental substitution expands temperature range of MCE FM
FM
-
Conclusions
Increasing TC
References 1 ElMassalami et al. J. Mag. & Mag. Mater. (2011). 2. Franco, V. Annual Review of Mater. Research (2012). 3. Isaac, M. and van Vuuren, D. Energy Policy (2009). Support: Army Research Office (ARO Grant: W911NF-10-2-0098 (subaward 15-215456-03-00)), Northeastern University
PM
PM
AlFe2B2 materials provide a broad temp. range for magnetocaloric & sensor applications Conserved unit cell volume through magnetic transition, avoiding degradation from repeated expansion and contraction Magnetic response may be tailored for sensor applications
Elemental Substitution for Designing ‘Cool’ New Materials:
Tailoring AlFe2B2 Magnetism-Structure Relationships for Magnetocaloric Applications Brian Lejeune & L.H. Lewis, Department of Chemical Engineering, Northeastern University
Abstract:
A new family of lightweight, inexpensive materials based on the composition AlFe2B2 with potential applications for sensors and magnetocaloric cooling is investigated.1 In particular, the magnetocaloric effect (MCE) can be utilized for CFC-free magnetic refrigeration to achieve 30-50% higher efficiencies than compression cooling, potentially reducing energy usage in a 200 billion dollar per year industry.2 The MCE is the reversible adiabatic temperature change of a magnetic material upon the application or removal of a magnetic field and is amplified in materials undergoing magnetostructural phase changes.2 In this work investigation of the magnetostructural phase transition in AlFe2B2 allows correlation between magnetic behavior, composition and structural properties. In this manner the phase change behavior may be tuned to different temperature and magnetic field regimes. Results indicate that composition alters the magnetic transition temperature of the system. Extending the range of transition temperatures achievable in the AlFe2B2 family of materials makes this a more versatile system for proposed applications.
Motivation: Novel materials support rising energy demand
Global energy demand (PJ)
Increased demand for global heating/cooling3
AlFe2B2 structure
AlFe2B2: New material for applications Inexpensive, produced from abundant elements Magnetic phase transition @ room temperature
Magnetic refrigerator
Cooling
Magnetized
Fe-B layer
Magnetic actuator
Magnetic field Heating Cooling
Al layer
Crystal
Heating
b
Demagnetized Mag. field
15% of worldwide energy usage is from cooling3
http://goo.gl/I89jlK
http://goo.gl/9Iqgi6
Jeitschuko, W. Acta Crystallogr (1969).
Results: AlT2B2 (T = Fe, Mn, Co, Ni) shows promise for magnetic refrigeration & sensing Response evaluated using the Magnetocaloric Effect (MCE) Adiabatic temperature change (ΔTad) of a material subjected to a variation in magnetic field ΔTad ≈ -(T/ CH )*∆Sm
Orientational relationship between structure and magnetism
Evidence of AlFe2B2 coupled structural and magnetic transition
Al13Fe4
Al
T = Temp. (K) CH = Heat capacity (J/kg-K) ΔSm = Mag. entropy change (J/kg-K)
Largest magnetocaloric effect near transition temperature
AlFe2B2
Strong correlation between Fe-B chains & magnetic response
200 micron
Conserved unit cell volume through transition
AlFe1.9T0.1B2 elemental substitution expands temperature range of MCE FM
FM
-
Conclusions
Increasing TC
References 1 ElMassalami et al. J. Mag. & Mag. Mater. (2011). 2. Franco, V. Annual Review of Mater. Research (2012). 3. Isaac, M. and van Vuuren, D. Energy Policy (2009). Support: Army Research Office (ARO Grant: W911NF-10-2-0098 (subaward 15-215456-03-00)), Northeastern University
PM
PM
AlFe2B2 materials provide a broad temp. range for magnetocaloric & sensor applications Conserved unit cell volume through magnetic transition, avoiding degradation from repeated expansion and contraction Magnetic response may be tailored for sensor applications
