Spin-polarized electron energy loss spectroscopy or SPEELS is a technique that is mainly used to measure the dispersion relation of the collective excitations, over the whole Brillouin zone.
Spin waves are collective perturbations in a magnetic solid. Their properties depend on their wavelength (or wave vector). For long wavelength (short wave vector) spin wave the resulting spin precession has a very low frequency and the spin waves can be treated classically. Ferromagnetic resonance (FMR) and Brillouin light scattering (BLS) experiments provide information about the long wavelength spin waves in ultrathin magnetic films and nanostructures. If the wavelength is comparable to the lattice constant, the spin waves are governed by the microscopic exchange coupling and a quantum mechanical description is needed. Therefore, experimental information on these short wavelength (large wave vector) spin waves in ultrathin films is highly desired and may lead to fundamentally new insights into the spin dynamics in reduced dimensions in the future.
SPEELS is the one of the few techniques that can be used to measure the dispersion of such short wavelength spin waves in ultrathin films and nanostructures.
Homework Statement
A 15.0 kg block is dragged over a rough, horizontal surface by a 74.9 N force acting at 17.6 degrees above the horizontal. The block is displaced 4.91 m, and the coefficient of kinetic friction is 0.266.
Find the work done by the 74.9 N force = 351 J
Find the work done...
Hi,
ok so everytime I think that I have understood the concept of Energy transmission, losses and voltage drop, I get even more confused about things.
I have searched several threads on this forum and the physics forum but failed to find anything that directly answers my query. So I...
Maybe this question has already been asked, anyway, here it goes. The universe is expanding and according to relativity, the radiation is redshifted, meaning there is a loss of energy. If energy is conserved, where does that loss of energy go?
I can't seem to get any of the answers for this - please help!
Two stars of equal mass M orbit a common centre. The radius of the orbit of each star is R. Assume that each of the stars has a mass equal to 1.5 solar masses (solar mass=2x10^30kg) and that the initial separation of the stars is...
Homework Statement
What is the energy loss in 3 mm of air (density = 1.20479E-03) of an electron with energy of 1.77MeV?
The Attempt at a Solution
I've found the Mass stopping power which is 1.696 MeV cm^2/g
and then linear stopping power of 2.04E^-3 MeV/cm
but from this point I'm stumped...
I've been thinking of developing a program which predicts the motion of two colloding billard balls, I wanted to encorperate some energy loss in the collision since its not an elastic collision.
My question is which root would be the valid or real result of a collision.
Imagine two billard...
Hi there...
My question is that when nucleon's loses energy (such as in fusion),does that affect their size as well? do they also shrink or grow by losing or gaining energy?
Homework Statement
We recently did a lab in my physics class where we looked at the conservation of energy of a ball on a roller-coaster track.
We got the data as seen in the picture below
http://tinypic.com/r/168zx2s/7
the question now is why is there negative energy loss, is this...
For an analysis of a robot component: a Spur gear drive/train.
How can I account for friction losses?
I can calculate the torque, with neglecting friction.
And what about the change in energy?
I know power = torque*angular velocity
Homework Statement
A block of mass 7.00×10-1kg is suspended by a string which is wrapped so that it is at a radius of 5.80×10-2m from the center of a pulley. The moment of inertia of the pulley is 4.00×10-3kg*m2. There is friction as the pulley turns. The block starts from rest, and its...
Homework Statement
An electron with energy 10^3 MeV collides with a photon whose wavelength corresponds to the maximum wavelength of the 2.7-K cosmic background radiation. What is the maximum energy loss the electron can suffer as a result of the collision? What is the wavelength of the photon...
Hi. Since photons lose energy when moving against gravity (because of gravitational redshift), there must be some other energy that is increased, i.e. the energy converts to another form. That other energy must be potential energy, right? But for a photon to obtain potential energy, it must...
Hi guys,
the Bethe bloch (BB) equation, in combination with the material density, gives the energy deposited in the material per unit path length. One of the terms in the BB equation is the maximum energy transferred to an electron by the incident particle. So i am assuming, the...
Is there any loss of energy of a particel (electron) while getting collission with the walls of a finite square/rectangular barrier?
since there is a enormous no. of collision a particle takes.
Homework Statement
In an RC discharge circuit, R= 2.5 X10^4 ohms and C=40 microfarad. The initial potential difference across C is 25 V. Find the rate at which energy is being lost by C at 0.5 seconds.
Homework Equations
The Attempt at a Solution
Like in this case, I probably have...
This might be a tired topic but please help me to understand.
Assume a photon moving in vacuum, ignore potential interstellar medium absorption and re-emission since it is not relevant to discussion of space expansion in this context.
Redshifted photons will undergo energy loss between *right...
This is probably a dumb question, but I only need to know for a program I would like to write.
Basically, on average (I realize there are a lot of factors involved, but a rough estimate is all I need), how much energy dissipates over a specific length of a conductor (power lines, whatever...
Homework Statement
For the LEP, we are given that it is a perfectly circular accelerator with circumference 25 km and that the energy of each beam is 50 GeV. Calculate the energy lost in GeV/s by a single electron on each turn.
Homework Equations
The loss is given by...
Homework Statement
Assume no friction. A 58-kg teenager at a water park slides down a long, winding waterslide of varying slope. The slide has a net height difference of 30. m from start to finish, and the teenager starts from rest. Throughout the problem, let y=0 and Ugrav = 0 at the end...
How can I calculate energy loss from a leak in a large furnace?
I currently am working on a large furnace about 1200 square feet. To heat the furnace we use a combination of air and methane at a ratio of 9.54:1. There is currently a hole in the furnace and I would like a formula to calculate...
I have air flowing through a gate valve with lengths of pipe of matching diameter upstream and downstream. At a certain distance from the valve upstream and downstream, I am measuring static temperatures and static and stagnation pressures. I can estimate the Mach numbers at the tapping points...
I have to find the kenetic energy lost in the problem. I have both initial and final kenetic energy, how do i calculate the percent loss? I tried final over initial times 100 but that is not correct.
Homework Statement
PART D
this is an example from my textbook, i do not understand the result however
Homework Equations
U = W = Q^2/(2v) = 0.5 CV^2 = 0.5 QV
the charge once connected
Q1 640 micro F
Q2 320 micro F
V1=V2 = 80V (equating the charges to total Q0...
Homework Statement
How do you find the kinetic energy lossed when you have equal masses in a collision problem?
Homework Equations
The Attempt at a Solution
[SOLVED-Thanks AL]Mechanical Energy loss due to NC Forces: two railroad cars collide.
SOLVED! - Thanks Al!
Homework Statement
Two railroad cars each of mass 4800 kg and traveling @ 80 km/h collide head on and come to rest. How much thermal energy is produced in this collision?
Homework...
Homework Statement
One hockey puck of mass 0.2 kg strikes an identical stationary puck on a frictionless ice rink. If the first puck had a velocity V0 = 3.8 m/s before the collision and V1 = 1 m/s after in the same direction, what fraction of the energy was lost?
Homework Equations...
If the energy of an EM wave = h x f
and when a light emitting body (of a particular power) is moving toward or away from the observer the observed frequency changes, does the energy change?
If so where does the gained or lost energy come from?
Hi,
This is about a basic fact which has never been clear to me.
As per the equation Work = Force x Displacement, if there is no displacement there is no work.
On the other hand, one of the exercises I do involves pushing a wall. I stand in front of a wall and try to push the wall as...
Homework Statement
picture: http://is.gd/tm7a
An apparatus to determine coefficients of friction is shown above. The box is slowly rotated counterclockwise. When the box makes an angle \theta with the horizontal, the block of mass m just starts to slide, and at this instant the box...
1. A ball with a mass of 0.5 kg is thrown straight up with an initial speed of 20 m/s. The ball reaches a maximum height of 15 m. (a) Give the energy loss due to air resistance. (b) What height would the ball have reached without air resistance? (c) What height would the ball have reached on the...
I need help with this problem where we are suppose to determine the fraction of kinetic energy lost by a neutron m=1.01u when it collides head-on and elastically with a target particle at rest which is.
examples used..
Hydrogen = 1.01u
heavy hydrogen = 2.01u
How would you do this?
Do...
If you raise the voltage you must raise either the current or the resistance since V = IR.
So how does a wire with higher voltage and lower current have less resistance?
It should have more resistance to make up for the lower current.
Hello,
I know that something around 65% of the potential energy stored in fuel is lossed in an engine through heat. I am trying to find exactly how its lossed, I know some is through piston friction, and some is lossed through the exhost, but I can't find how much is lossed for each...
Homework Statement
In the year 2000, the highest energy beams at LEP were achieved, at E = 104.5GeV.
a) Calculate how much larger was the synchrotron energy loss at this energy, relative to the synchrotron energy loss at E = 45.1GeV
Homework Equations
E_{loss} = (E/m)^4 x...
Hello. I've recently been using a few different numerical integration methods to solve a number of different problems, and as I looked into the integration algorithms, I realized that I don't understand them as well as I thought I did. I created a simple Excel workbook that calculates the...
I'm "aware" of current theories about the cyclic model but what's wrong with this hypothesis?
The universe starts crunching forming a big black hole
All the energy is sucked back into this big black hole
The big bang starts again with all the matter and energy as the previous big bang...
Tried to figure this out for a friend but couldn't quite get it. Here is the problem.
For 3 hours one winter afternoon, outside temp is 0* C. A house is heated and kept at 20* C with the expenditure of 45 kwh. What was the average energy leakes in joules per second through the walls of the...
Hello,
I'm working on a Time Of Flight simulation to detect some pair/particles and I need some information about the "Energy dependence of the light yield of PST scintillators"
Does anyone have information about this?
Thank you in advance.
Circuit 3(connected to a 3v battery,C2 and C3 in series, C1 and C23 in parallel)
C2
C1
C3
c1=c2=c2=1F
Circuit 4(Two unequally charged capacitors are connected to each other,from setup above)
C1 C2
In circuit 4, after the...
How can I measure the total energy loss of a Newton's cradle until it comes to rest. The only variables I am given are the horiztonal displacements for each swing (how far the ball travels out after it rebounds off the other balls) and the angle. I have no idea where to start, I was told I...
A parachutist with a mass of 50.0 kg jumps out of an airplane with an altitude of 1.00 x 10^3 m. After the parachute deploys, the parachutist lands with a velocity of 5.00 m/s. Find the energy that was lost to air resistance during th jump.
I tried using this: W = Kf – Ki → W = ½ mv^2 (f) –...
I'm doing research on window functions (such as: rectangular, Hanning, Blackman, etc), but am having trouble with respect to the energy loss associated with each. I know that applying the window causes energy loss in the spectra of interest, and for the Hanning Window and Hamming window...
I'm doing research on window functions (such as: rectangular, Hanning, Blackman, etc), but am having trouble with respect to the energy loss associated with each. I know that applying the window causes energy loss in the spectra of interest, and for the Hanning Window and Hamming window...
new problem!
A pumped-storage reservoir sits 136 m above its generating station and holds 9.0×10^9 kg of water. The power plant generates 346 MW of electric power while draining the reservoir over an 6.9 h period.
What fraction of the initial potential energy is lost to nonconservative...
i was doing a little thinking and have a pretty good idea but to see if it will even come close working i need to know how much energy loss is there converting water to hydrogen then back to water. using Electrolysis to split the water and a fuel cell to rejoin them back together. i know you...
Hi guys,
can anyone help me with this question?-
An optical fiber has a loss of 0.8dB/km at a wavelength of 1250nm. If 120uW of power is injected into the fibre at the transmitter, how much power would be lost at a distance of 20km down the fibre, also calculate the energy loss over a 24hr...
A 575 kg satellite is in a circular orbit at an altitude of 550 km above the Earth's surface. Because of air friction, the satellite eventually falls to the Earth's surface, where it hits the ground with a speed of 2.10 km/s. How much energy was transformed to internal energy by means of...
Hi,
I believe that the free electrons in a piece of a conductor move randomnly until they are oriented in one particular direction by some external field. Does free electrons lose energy in this random motion??:confused:
Lets say you have a ball on a ramp (hight h). It rolls down to the ground and then starts moving at aconstant speed - no friction (ok don't kill me, it's not really rolling either, just sliding). Now to the point of view of someone moving at the final speed of the ball and in the same...
Hi all,
I'm having a problem with this subject and I was wondering if anyone could confirm/comment on my understanding.
As I understand it, in a typical transformer, an AC current is supplied to a primary coil which induces an oscillating flux within the core. If the core is made of a...